I have. I set mine up to have a min/max number of playlists. Right now its set to six because thats the number of playlist buttons I have on the skin I'm working on. But it could be any number you wanted it to be. Here is my code from ExecTBL.ini...
Since VB doesn't really distinguish between chars/strings/integers you can do a string compare against your upper/lower bounds. The EVAL strcomp returns a 1 if your at your min/max. Using BYVAR I then increment/decrement if EVAL statement returns a 0 (you're not at either bound). If it returned a 1 then I do nothing. The current playlist number is saved to skin.ini so that it doesn't reset everytime you reload RR.
/, Custom Increment/Decrement Commands for Playlists
/, Car2PC Commands
I've tested this and it works great. You can change the number of possible playlists by modifying the "6", and "1" in the two Car2PC command lines. This is probably clear as mud, but it really does work well. Knowing you though, you've probably got a cleaner solution already.