You can use the model pack 6 stuff with FPSc x10 if you follow the instructions in the first post.
The hands need retextured if you're not happy with the way they look.At this point they beat anything I can come up with.
I didn't test the flak weapons in x10 though so I don't know about them.
If you want any information about the conversion of model pack 6 or any other model pack to x10 then read the September newsletter (if you have been naughty and haven't subscribed to it..it's free!)
and you can find the link in a sticky at the top of the Geek Culture forum.
There are a variety of media available that will work with x10.You just have to test it out to see one way or the other.
Failing at every guitar game ever made!