Originally posted by 6BQ5 I would be hesitant to believe that Ricoh will introduce a fourth mounting system. They already have the Q, K, and 645 systems to sustain. A fourth could take away precious resources from existing systems. Ricoh has stated that their mirrorless solution is the Q system. So, unless they plan to abandon the Q in favor of something else I don't think we'll see a larger sensor system.
Then again, who knows? We're all just guessing here.
I think eventually thy'll have a system above the 645--like the old 67 system. Personally I'd suggest a mirrorless 67 with a registration distance of ~60mm. That way the 645 takes over the studio shooting, while the 67 can venture into the high end wedding & landscape shooting. They'd need a very wide diameter mount to ease the angle of incoming light at the edges of the sensor and I'd advocate for in-lens leaf shutters to minimize body depth and noise. I'd suggest a lense lineup of ultrawide, wide, short normal, and short tele with possible fisheye, macro, and shift specialty lenses. Of course I'd never be able to afford such a system, but it would be the holy grail of photo hounds!