It's probably just a technology demonstrator sensor demonstrating that their techs can scale up the S10/S11 technology to APS-H levels. Actually mass-producing such a device would most likely be outlandishly expensive with current fabrication processes; I wouldn't be surprised to see $500 or above per sensor. Also, can you imagine the MTF needed on lenses for this system? You'd be lens-limited until Canon could hire Carl Zeiss off Sony to produce $10,000 lenses. And how about post-processing the damn thing? You will be dealing with 120 MP raw files. You're probably already shelling out 4 digits for EIZO LCDs, are you looking forward to buying dual GTX480 ($500 or $600 a pop) GPUs to fuel CUDA-based Photoshop CS5, along with a $1000 CPU and probably 16 gigs of ram?
I think the only way to bring this to market would be to market it as a ridiculous sensor toy in an MF-like modular camera; you'd get upgradeable DIGIC processors starting at 1 fps, and then later on as processing improves you'd move up to 8 or 10 fps. Your lenses would be completely inadequate, but if you own a very high-end outfit I suppose you could wow clientele with your $100,000 wanna-be medium format.
Dynamic range does have an inverse correlation to pixel size, but it's not as bad as people make it out to be; 120 MP would have more than 6.6 times the signal to noise ratio than the 7D based on megapixel increases while ignoring the effects of the smaller sensor size.
Looking at the G11's dxomark data, it would have a 3rd of a stop less full-picture performance or identical performance at ISO 3200 than the existing 1D4, depending on how you treat manufacturer ISOs and between one stop and five thirds of a stop less full-picture performance than the D3s, depending on whether you consider the fact that the D3s's manufacturer ISO 3200 is somewhat below the G11's. In Dynamic Range, using SnR comparisons, which is typically valid for "usable dynamic range", but not total dynamic range, the 120 MP super G11 would scale to about 14 EV, which is above the D3x, I believe.
DLA for the 120mp APS-H should kick in around f/4, I believe, so everyone would be advised to use f/2.8 lenses, further adding to the cost.
Everything considered, I would be willing to buy a 120mp APS-H provided that I had the million dollars needed to pay for the camera, the lens, the computer, and nothing better to spend it on. Even if I were severely lens-limited, compared to the existing cameras, think of the ISO 50 resolution on this baby! It would be able to resolve at least twice the MTF detail over existing devices, and when sensors do catch up you'd be able to do micro-biology with macro lenses.