I'd give the Bren II a long hard look first, then I'd consider an Ace, Makasi or Zpap 90 if you want to stick to standard rifles. If you're willing to consider a bullpup, I'd slot the X95 in right behind the Bren and then the AUG in order of consideration.
I like my standard RDB a lot, but the chamber access issue has it off the table for a serious gun. Great range and competition toy though.Prolly an RDB Survival or whatever they're calling it now. Just picked up my second one last week. Yeah, it's non-standard in form and appearance but it fills a niche no other rifle does. I know,...I know,....you think it's freaky looking. Absolutely, it is, but it's the coolest lil' rifle I've ever held/fired and I have a small room full of SBRs. This thing rocks.
KelTec also makes a very similar rifle with a longer handguard and 20" barrel instead of the 16". If anything, I like that one even better but it doesn't quite fill the same niche as a non-NFA 22" rifle with a 16" barrel. Oh, you can buy one of each for the $2k you're considering.
Galil Ace II In 5.56
Some kind of bolt action rifle that accepts AR-15 magazines. Ruger American Ranch or Predators, CZ 600 has a model I think that accepts AR-15 magazines.
BRN180 can be a pretty cool build with the retro lower and a folding stock.