I know this isn't possible right now, but the res is within the limits of DVI-D. So why haven't we seen it fruit up anywhere? Is 1600x900 that new? It would be nice for those who have 16:9 monitor to get something heigher than 720p or 768p.
As monitors increasingly head toward 16:9 aspect, I wouldn't be surprised to see it become a possibility. You're right that 3 x 1600 x 900 should be possible cablewise if it can already handle 3 x 1680 x 1050.
It's going to get harder and harder to buy 16:10 monitors in the future, which has me wondering whether or not to invest heavily in the TH2G and risk it or looking at ATI's Eyefinity.
I already use a TH2G and am pretty happy with it, but am building another 4 machines so I'm keen to get it right.