AFAIK officially no.
You can save some poses, change the skin and some shaders... No real customization beyond this.
Inofficially (not illegally!), I found no simple way, too.
I've checked this right after getting bored with the alpha, but couldn't find something obvious.
I have poked around a bit in the game files and internals (like I guess many others, too), found the textures and stuff (mind the copyright!) but it looks to me more or less like it was back then with the very early VaM versions, before the customisation features were build in. Back then, we had tried everything to mod the stuff, with less than zero results. On the other hand, the community is much bigger and we have a lot more experienced plugin programmers and Unity experts now...
