Well Jim Klein (who I don't know but love his work now, and these pics were not used with his permission but thay are really cool. Hope you don't mind if I spread the word a little Jim) offered up this great take on them as well:
Brilliant. I love it. When I got the mercenary sculpts, this was the first thing I thought about. Wow those would be great space orcs. I decided to not do them that way cause I wanted to go a different way. But now, I may need to get some more packs so I can do them just like this. I have a bunch of 15mm Armor that could proxy. And I already have a bunch of notEldar I picked up.
You could then play large battle with In The Emperors Name, or use FUBAR or anything else. With all this OldHammer/Rogue Trader nostalgia going on, you could easily proxy all the great early stuff and have some fun. I know that Blue Moon does some great potential stand-ins for Marines.
Anybody else got some suggestions for proxies? With Demonworld's line now being reporduced, I bet with some work, you could have some Dark Eldar and Squats pretty quickly.