Im in the same boat mate, gonna sell of my 1080's and get 1080Ti lack of SLI support and bugs are pissing me off, that said in games like Division or GTA V I will be worse off, oh well I'll probably buy a 2nd one later on anyway.
Any word on when are they actually coming in stock ?
Not sure on founders but other companies might be putting some in stock on the 10th.
As far as SLI goes, I'm probably not going to venture into that again since it seems lesser games seem to be supporting it these days. It's really nice to get 100+ fps at 4k when it works but sucks when it doesn't and your second card is a paperweight in the game. I know I'm going to lose FPS in dishonored 2 but oh well. I think the 30-40% increase in single card performance at 4k makes this worth it.