Hmmm. Are you sure there is nothing already ready to copy and paste lost here in the forums?
Anyways what are the rules?
Initiative is speed based or will be luck based?
Does strength affect damage or it will be based in firepower?
Dash/run? Block? There will be armor and action points?
Can you offer surrendering to your enemies? Or is a fight to the end.
There will be rewards to the winner?