Non-Lethal Damage

[Olaf the Stout]

Sounds about right.
I'm not sure about the "subdual = hp" part though. I think it's more like negative hp, in that you still have too much damage but are concious and staggered/disabled anyway. The state goes away when you aren't all beat up.
Remember that subdual damage heals at the rate of character level / hour rather than per day.

ValhallaGH, that also makes sense the way you describe it. Either way would work I think.

Olaf the Stout