Oh, slight update on the battle royal system...
I bounced some ideas off of Ringman and we discussed various systems. The best way to do this would be Wushu, as it was developed for a forum to begin with. It can be modified easily for an all-action system, with modified stats.
I'm also looking into
Basic Roleplaying System, which is used for the Call of Cthulhu game. Call of Cthulhu is a primarily story-based system, and I was thinking of modifying it for the forum. However, if you look through those rules, you'll notice the other rules for loot, experience, usage of a d100, and such.
The parts I'm considering using from those rules would be the resistance table, stats, and the percentage die (which I have). I'll work on a system from that and play test it and see if it works.
Basically, when we hashed this out, we determined that in order to keep god-moding to a minimum, there needs to be a random element. The system won't work without that element, be it a table, a coin, or dice. Having one person as the designated DM would be the best idea, as they can oversee all the other stats.
Modifying Wushu would be the best way to go, as it can be slimmed down to just stats and dice rolls. I'm still looking at the BRS, though, and I'll do some searches for other forum RPG systems.