I'm not sure if its possible or not to bring it to css but there is a lot of MW stuff at Left 4 Dead 2 Workshop (like operator, etc) It would been cool to have it on css but ofc with premission from the creator itself
This is for non steam version, but I think it'll also work with Steam version as well... As for beta test then might have to wait for a while since its still no fully polished and i've been kinda busy with IRL stuff