Thanks, OP, for the question... I'm in a similar boat and asked a couple posters I respected an almost identical question via PM. I started with a PM mainly because I wasn't sure whether or not posting a thread would contribute even more to all the crazy speculation that's happening here.
For what it's worth: I'm trying to finish two 'tactical carbine' builds and tweak out my existing 'precision' AR. My plan is to, as soon as possible, purchase the lower parts kits I want (with either MOE or CTR collapsible stocks) as soon as I can reasonably do it. My hope is that I can do that well before any legislation really starts to get wings. Then, I can have the lowers, which are the rifle after all, completed.
I'm suspecting that uppers will continue to be available (at least for a little while) since they are not technically a firearm. If an eventual ban does take away a bayonette lug or flash hider from my eventual uppers, I can live with that.