I wonder why no MFDB has gone CMOS? A double-size D800E sensor might be much cheaper to produce than the IQ180 sensor, and perhaps as good?
I think it is because that it is not so easy. Today only Sony can make CMOS sensors that is up there competing with MF CCDs in performance. Canon can't, Nikon can't (but use Sony sensor in D800), Dalsa can't. It is also a bit tricky to make large chips, so it could be the case that noone has the technology to make a CMOS chip of that size (which are more complicated than CCD). Concerning cost my guess is that it would be more expensive to make due to being more complicated, perhaps leading to lower yields.
Fast refresh liveview directly on the back, great ISO performance, long exposures, comparable (or perhaps better) low ISO performance. It would surely be a market for that thing, but someone must have the capability to manufacture it. Sony may be able to do it, but MF would be a whole new market for them, and much less profitable than the smaller sensors. We will see what happens.