Hi folks,
I'm happy to report that I'm finally in a possession of a GR for the test and review! I'm now a part of GR Ambassador program, which means I'm supposed to take some photos and put together my thoughts about the GR. Then I will join the existing number of GR ambassadors at special GR site:
http://gr.pentax.eu I will do my best to put together some nice photos and stay as objective as possible in my review

The first test I did after receiving the camera, and after setting it according my taste, was something I was quite curious about since the GR announcement. Will the GR works with the "ancient" GT-1 tele extension lens, originally developed for GRDI and II? As you may remember, I found the GT-1 lens practically useless with the GRD III and IV. The main reason was its brighter f1.9 lens and wider lens barrel. True, the GR lens barrel is even wider, however, it's also much shorter and the lens lowest f number is now 2.8. And these changes in GR design put me in a hope of a possible GT-1 reborn.
Because I don't have the GH-3 adapter yet, all I could do so far is a quick hand-held test. But even this unscientific test says that the GR+GT-1 looks promising! Although the GR+GT-1 combo will never win a corner sharpness contest, the center sharpness seems to be great. I would never use this combo for landscape photography, but it may be great addition for portraits? Stay tuned for a proper shots with GH-3 and comparison of 28mm, in-camera cropped 35mm mode and 40mm GT-1 test!
These are unmodified photos taken with GR + handheld GT-1:

- R0000260_sm.jpg (334.96 KiB) Viewed 10577 times
- EXIF-Data
- Image taken on: Sun Sep 29, 2013 7:56 am
- Focus length: 18.3 mm
- Shutter speed: 1/125 Sec
- F-number: F/4
- ISO speed rating: 400
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- R0000261_sm.jpg (343.21 KiB) Viewed 10516 times
- EXIF-Data
- Image taken on: Sun Sep 29, 2013 7:58 am
- Focus length: 18.3 mm
- Shutter speed: 1/200 Sec
- F-number: F/4
- ISO speed rating: 400
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- R0000267_sm.jpg (539.59 KiB) Viewed 10548 times
- EXIF-Data
- Image taken on: Sun Sep 29, 2013 8:01 am
- Focus length: 18.3 mm
- Shutter speed: 1/200 Sec
- F-number: F/4
- ISO speed rating: 400
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- R0000272_sm.jpg (540.64 KiB) Viewed 10504 times
- EXIF-Data
- Image taken on: Sun Sep 29, 2013 8:05 am
- Focus length: 18.3 mm
- Shutter speed: 1/200 Sec
- F-number: F/3.5
- ISO speed rating: 800
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average
Below shots show a real edge sharpness of GR+GT-1 combo and comparison with native 28mm and 35mm crop mode. Once again, these shots were taken by landholding the GT-1 in front of the GR lens, so they are not very scientific and precise example how the sharpness may look with GT-1 attached on GH-3.

- 28mm_f4.JPG (978.55 KiB) Viewed 10195 times
- EXIF-Data
- Image taken on: Fri Sep 27, 2013 5:52 pm
- Focus length: 18.3 mm
- Shutter speed: 1/250 Sec
- F-number: F/4
- ISO speed rating: 100
- Whitebalance: Auto
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Aperture priority
- Exposure bias: 0 EV
- Metering mode: Center-weighted average

- 35mm(crop)_f4.JPG (993.05 KiB) Viewed 10167 times
- EXIF-Data
- Image taken on: Fri Sep 27, 2013 5:53 pm
- Focus length: 18.3 mm
- Shutter speed: 1/200 Sec
- F-number: F/4
- ISO speed rating: 100
- Whitebalance: Auto
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Aperture priority
- Exposure bias: 0 EV
- Metering mode: Center-weighted average

- 28mm+GT1_40mm_f4.JPG (778.65 KiB) Viewed 10097 times
- EXIF-Data
- Image taken on: Fri Sep 27, 2013 5:55 pm
- Focus length: 18.3 mm
- Shutter speed: 1/200 Sec
- F-number: F/4
- ISO speed rating: 100
- Whitebalance: Auto
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Aperture priority
- Exposure bias: 0 EV
- Metering mode: Center-weighted average

- 28mm+GT1_40mm_f8.JPG (889.75 KiB) Viewed 10068 times
- EXIF-Data
- Image taken on: Fri Sep 27, 2013 5:56 pm
- Focus length: 18.3 mm
- Shutter speed: 1/45 Sec
- F-number: F/8
- ISO speed rating: 100
- Whitebalance: Auto
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Aperture priority
- Exposure bias: 0 EV
- Metering mode: Center-weighted average

- 35mm(crop)+GT1_50mm_f4.JPG (834.23 KiB) Viewed 10039 times
- EXIF-Data
- Image taken on: Fri Sep 27, 2013 5:58 pm
- Focus length: 18.3 mm
- Shutter speed: 1/180 Sec
- F-number: F/4
- ISO speed rating: 100
- Whitebalance: Auto
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Aperture priority
- Exposure bias: 0 EV
- Metering mode: Center-weighted average
If you are interested, you can find full resolution photos here:
http://www.flickr.com/photos/odklizec/s ... 045019106/I'm sure both girls will shoot me one day for posting their photos

EDITED 4.11.2013:
The GH-3 finally arrived and over the weekend I got a short chance to take some photos. As I've expected, the GH-3 did not improve the corner/edge sharpness degradation. In addition, the combination of GH-3 and step-down ring made the vignetting noticeably worse. Apparently, during the handheld test, I was able to hold the GT-1 at much closer instance to the GR lens, which effectively eliminated vignetting. On a positive side, the GT-1 seems to be still somewhat useful for portraits with a lot of blurred background around the photographed subject, where the corner/edge softness and vignetting could be effectively masked out. Here are some new photos taken with GR + GT-1 using GH-3. For full res photos (and some more) photos check this flick set:
http://www.flickr.com/photos/odklizec/s ... 045019106/

- R0001417_sm.jpg (467.38 KiB) Viewed 9136 times
- EXIF-Data
- Image taken on: Fri Nov 01, 2013 10:20 am
- Focus length: 18.3 mm
- Shutter speed: 1/80 Sec
- F-number: F/4
- ISO speed rating: 800
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: 0 EV
- Metering mode: Center-weighted average

- R0001425_sm.jpg (453.96 KiB) Viewed 9073 times
- EXIF-Data
- Image taken on: Fri Nov 01, 2013 1:48 pm
- Focus length: 18.3 mm
- Shutter speed: 1/60 Sec
- F-number: F/4
- ISO speed rating: 1600
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: 3/10 EV
- Metering mode: Center-weighted average

- R0001439_sm.jpg (459.14 KiB) Viewed 9110 times
- EXIF-Data
- Image taken on: Fri Nov 01, 2013 2:48 pm
- Focus length: 18.3 mm
- Shutter speed: 1/1250 Sec
- F-number: F/2.8
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- R0001446_sm.jpg (513.99 KiB) Viewed 9044 times
- EXIF-Data
- Image taken on: Fri Nov 01, 2013 2:50 pm
- Focus length: 18.3 mm
- Shutter speed: 1/2000 Sec
- F-number: F/4
- ISO speed rating: 400
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- R0001493_sm.jpg (328.83 KiB) Viewed 9027 times
- EXIF-Data
- Image taken on: Fri Nov 01, 2013 3:30 pm
- Focus length: 18.3 mm
- Shutter speed: 1/2000 Sec
- F-number: F/5
- ISO speed rating: 400
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Not defined
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- R0001551_sm.jpg (502.05 KiB) Viewed 8998 times
- EXIF-Data
- Image taken on: Fri Nov 01, 2013 3:59 pm
- Focus length: 18.3 mm
- Shutter speed: 1/500 Sec
- F-number: F/4
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Aperture priority
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- R0001556_sm.jpg (431.32 KiB) Viewed 8998 times
- EXIF-Data
- Image taken on: Fri Nov 01, 2013 4:09 pm
- Focus length: 18.3 mm
- Shutter speed: 1/350 Sec
- F-number: F/4
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GR
- Exposure program: Aperture priority
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average