In gr it is commonly done, you need the nwest plugins for #ds as well as a good tutorial. Go to
http://www.piggyson.com for those, it'll set you up. As for the RS character editing, I used to do it all the time (think-Renegade Legion), you need a copy of milkshape3d, Mike Schell's CRP<=>DXF convertor, and some patience. I have no idea where to find the convertor now, I lost mine when I had a crash this year. The piggyson site also shows how to make weapons, or check out
http://www.planetrainbowsix.com/atwar for more tutorials and a ton of tools.