Looking at the marketing side and possibilities of this new approach by Canon, it obviously is in direct competition to Nikon's D800 and with the masses focused on qty of MP, Canon is making sure they are at least more than 10% larger than Nikon's sensor.
My guess is the IQ will be much much better than the D800 and 5D3 with some of the trade offs inherited by this newer technology such as FPS and high ISO noise.
Should this new model 'fail' to get the market share, then Canon has dug a big hole for themselves. This HAS to work OR they have to have another trick in the bag.
As far as pricing, my 'guess' is around $4,200.
5D3, 6D, 1D4, 16-35 2.8L ll, 50 1.2L, 50 1.4, 24-70 2.8L II, 135 F2.0L, 200 F2.8L ll, 70-200 2.8L II, 70-300L, 100-400L, 24 TSE L II, 85 1.2L II, 100 2.8L, ZEISS 100 2.0, ZE 50 2.0, ZE 35 2.0, ROKONON 35 1.4, SIGMA 35mm f1.4, SIGMA 85 f1.4, S110, S100, sony RX-100 and one big-a$$ bag