AT-43 models look to be a very good fit for UWZ proxies. I was actually looking at picking up a few myself to serve as proxies, but have become side-tracked by another big life changing event.
Fantasy flight and a couple of other places were blowing out AT-43 figures for about 75% off last year. You may still find the clearance stock on the FF website, and I think the War Room or Miniatures Market also had clearance stock.
BTW, the Kerans - Apes, might make for a new home-brew faction. They have power suits ala Vulkans, as well as normal infantry types.
Hope this incomplete information helps!