Brazilian Rainbow Boas get 5-7 feet
Totally a manageable size, and they're absolutely gorgeous too of course
ATBs stay pretty small too, but most of them are pretty nasty temperament wise...
Solomon Island Ground Boas are cool... Spotted Pythons... Dumeril's boas stay a bit smaller than the red tails... I'm sure I could come up with more, but that's all I can think of right now
Hope that helps a bit