The Q sensor is a 1/2.3" (6.17 x 4.55 mm) ladies pinky fingernail sized thing. My other half's Canon SX230 uses the same sensor I think. It's a very good BSI-CMOS sensor, which my P10 struggles to match in bright light at the far end of the zoom. (the P10 slightly better under cloud though). But I'd like to see the bigger 1" sensor in a GXR unit, whatever mount is used, because IS could be squeezed in with it I think. The image circle on Q lenses would be too small for that sensor wouldn't it?
The S10 is basically a GX200 lens in a GXR unit. And a very good unit it is, I've bought one. But I can't think of this as a successor to the GX200. It's the same lens and sensor with slightly better exposure control and metering from the GXR body as far as I can tell. The GX300 should be something more like the new Sony RX100 which squeezes a 1" BSI-CMOS sensor and bright lens into a body less than the size of the old GX200. With a hot-shoe and a bigger battery inside a bigger grip, it looks good to me as a worthy GX300. And the same IS module and sensor could be fitted into a GXR unit I would hope.
So which mount would best suit it? The Nikon J1/V1 uses the same size 1" sensor and its lenses are a bit bigger than the Q and a bit smaller than Micro 4/3 lenses. Maybe there is the opportunity for the new range of GR lenses which you spoke of? 'Micro' PK mount?
In the meantime, I may take up your idea of fitting a PK adaptor to an A12 M unit, if I don't get offered an A12 28. Can't afford both at the moment.
Or a bagful of Leica and Zeiss lenses






