If it proofs to be a succes and if pentax did not taylor the design too much to the specific sensor, even if it not has a removable back, we might see higher mpx version too by replacing the sensor pcb and a few other components.
A good hint could be when someone discovers that the finder is masked off and the mirror is bigger then needed just for 44x33 chipsize. If I had to design such camera I would for shure think about that.
dammit :-) it isn't yet here in the west and we already think about future versions.
Do they even need to accommodate a larger sensor? With the advances made in sensor performance/size, could 33x44 be where the development's going? I believe I read here once that it's a lot less difficult to manufacture than a larger sensor (by quite a bit more than the surface area would indicate - I think it requires significantly less stitching - maybe it can be done with one stitch, while the 36x48 has to be stitched in both directions?). This WOULD require them to come out with one lens that is wider than anything they have now (a 35 is as wide as they go, while 33x44 really benefits from a 28, or if they want to shock everyone, a 24). They don't have the same worry about legacy lens collections as Phamiya or Hasselblad, simply because there haven't BEEN many Pentax 645s in active use recently - this is a camera that is meant to capture high-end DSLR users, NOT to digitalize existing MF systems. I hope we see it outside Japan.
I wouldn't want to be Canon right now, at least on the 1Ds 4 front, trapped between the D3x and this thing! Realistically, the Pentax will enter into just about every buying decision on a very high-end DSLR (some of which are also complicated by the M9). Not every 1Ds4/D3x buyer will choose the Pentax instead, but they'll all give it a close look. It MAY have the effect of not letting Sony into the really high end of the market, if they had any interest. I'd think it a rare buyer indeed who opted for a hypothetical $6000-$8000 Sony over the lens line security of Nikon or Canon OR the larger sensor offered by Pentax (unless the Sony had RED-level video, which would really stir up he market). THAT would be an interesting $6000-$10000 camera market!
1 rangefinder not that much larger than a G11, but with superb image quality - don't even think about video, you don't have AUTOFOCUS (Leica M9)
2 full system DSLRs with no or limited video(D3x/1Ds4)
1 DSLR with a more limited lens system, BUT with raw video (Sony "Alpha 1000")
1 or 2 medium-format systems with ultimate image quality, but less versatility (Pentax and maybe last year's Hasselblad - they're promoting the H3DII-31 under $10k right now)...