It's all been done before:
Breaking 50 paintball mod for COD1 and COD:UO circa 2005:
http://www.moddb.com/mods/breaking-50
The same team went on to port it to COD2 and COD4. I can't find any videos of them other than the COD4 port:
http://www.youtube.com/watch?v=mZf-KCEA3rc