I realize you're not trying to be rigorous, but you left out something important in Ghost. The way you have it now, someone could keep throwing in X's and Z's and the game goes nowhere.

There is supposed to be a rule that when you add a letter which does not form a word, you need to have a word in mind that can be spelled using the portion that exists. If another player thinks there is no such word, he can challenge you. If you can name such a word, you win. If not, the challenger wins.

I hadn't heard of Super Ghost - brilliant idea! == Johnny in OKC