There are a whole bunch of them at
MATY.
If you're looking for other CS stuff, there is plenty throughout
here. Just look for anything with "CS" in it.
(just so you know - MATY is often slow in loading).
I think making CS clothing basegame compatible is a little more difficult than just converting them with SimPE. Something about the files being different, or the skeletons, or something along that line.