You said 5.1. So, you need an in-wall sub as well for under $1k for 6 speakers? That will definitely knock a lot of contenders out.
No
Wisdom Audio, no Triad, no RBH and no BG Radia at that price.
I'm not sure about Def Tech. However, Monoprice, The Speaker Company, Aperion Audio and Infinity (get a non-Infinity in-wall sub) (See the Harman E-bay store or the Audioholics store.) are all doable for that price.
If you're willing to do on-walls, check out Axiom and EMP (at the Audioholics store!) as well.