Kyocera wont probably develop a G3 now. We may have to live with that fact for a certain time.
But it may be possible to upgrade the G2. G1 have already been upgraded : ROM upgrade (green label in the film compartment). It may be possible to add a few custom functions : other ways to control the existing hardware.
First : shutter lag/lens parking stuff : a custom function (call it "6") to enable another way of setting the lens to the desired focus, like what is done with the T3. Set to "0", same as today, set to "1", the lens is focused to the desired distance by the focus lock button, and doesn't move until another pressure on that button or until the camera is switched off. There is a risk : if the lens is set to infinity, and directed toward the sun, the shutter could be burnt after a while. But I think it's worth the game : no shutter lag when using the G like some use their Leica M.
Second : DOF scale : a custom function (call it "7") to enable another way of displaying the distance in the viewfinder : set to "0", as today, set to "1" : the square dots would indicate the DOF, and the "arrow" dot (used for manual focusing) would show the focus. A good figure if better than a big explanation, so have a look at the G2 manual, page 36 (hope it's the same for everybody) : "display in the viewfinder" : just imagine the square dots only show the DOF... Of course, the apperture of the lens cannot be transmitted by the lens itself, but is gessed from the difference between the internal and external meters.
Those 2 functions should, IMHO, greatly improve the G. There is no need to change the existing devices inside the G. An upgrade of the brain (software) should be enough. It has been made for the G1 (green label). I would pay to send my G2 to have it's ROM updated because I would get a much better camera. The cost for Kyocera R&D should not be that big, so it may be possible.
There may be other ways to design those custom functions, and other "desirable" customs functions. We shouldn't ask for too many modifications, too expensive for R&D.
Why not work on that and loby on Kyocera to make some ROM upgrade for the G ? It may be more real than an hypotethic G3. (a 11-13 M full frame digital G3 would for me be a good addition to the existing)
sorry for the long post