wolpi, I cannot give you any fixed estimate, but I can tell you one thing. I (and many others) have been waiting for a large mono new-generation CMOS chip for many, many years. Actually I have used the CCD chip KAI-11002ME for last 8 years as there wasn't anything newer or better.
And there is no any sign of anything that a 36x24mm mono chip will ever hit the market (not speaking about being in any reasonable price range that it would ever make sense to make it to the astrocamera)...
I could give you an estimate of 6-7 years from now :-) things are improving and we finally see some signs of new chips coming out. Unfortunately, there are either smallish (like 17mm diagonal or so) or ultra large (60-70mm diagonal). The large ones, like e.g. IMX411 are nice and great, but the price will be like $15.000-$20.000,- and even a Tak FSQ-106 would have issues with the corners...
to end with an optimistic comment - there will soon be at least APS-C mono cmos chip on the market later this year... AFAIK it won't have the greatest performance like some other 1/2" tiny chips, but reasonably well compared to 30 years old CCD technology...
