The DR650 would be a good first dual sport, but not ideal for multi-state rides (they can do it though). You can pick one up for a few thousand, you can get lowering links for them, and MMoto in the Ukraine makes a very stout rack that will carry your gear.
If you are looking for something more refined, the BMWs get good reviews, and are easy to mod with some pretty tricked out aftermarket stuff like racks, lights, electrical plugs, and all of that. You'll pay for it, though.
The Triumph 800XC may be too tall. A KTM 690 might work too (haven't sat on one, so I don't know how tall it is).