You know how the vanilla zombies in L4D can climb on almost anything? Could you possibly make that available for players? Maybe in the form of a “pill” that transforms you into a L4D zombie that can do all they do, or whatever other ways you can think of.
You’re probably going http://img405.imageshack.us/img405/2499/b03e12.gif, but I would more than love to see something like this get done.
Edit: I’ll just take that as a “You’re not well known enough to make requests.”