First of all, Badspot made it possible to only change your player every second. That's not really going to lag a server that much at all...
And there has been a mod like that, if you changed your player in a very short amount of time, your player would turn into the default blockhead, and you would have to turn off the script, then change your player back.
It probably won't work anymore, due to the new update that keeps you from changing your player fast like that.
Also, omg, I didn't spell anything wrong in that.