Been playing CS since the original HL mod was made. I found unfortunately that things remained pretty much the same through the history of the game (CS, CS Steam, CS:CZ, CSS) only the graphics got better.
I have played BF2 after that, but I have to say that I also got tired of it eventually.
The idea of RPG in CSS sounds puzzling though, where would I go to try it?
On a parallel subject, My bro and I are working on a Savage Mod including some RPG elements, you could have a look at this post: http://www.evolvedclan.com/forums/index.php/topic,1394.0.html