Well, as for nonlethal damage, we do as following.
For every consecutive hit (i.e. at least one per round) after the first, the attacker gets +1 to overcome the MAS of the target. For every round that goes with no hits landing (or not penetrating damage reduction), the bonus goes down by 1 (to a minimum of 0). So, this boxer-guy, with Improved Brawl and Improved Streetfighting, deals 1d8+1d4+2+5(Str)+2(MeleeSmash) = 9+1d8+1d4. That's an average of 16 points of nonlethal damage on the first hit. We use some alternative KnockOut Punch rules, inspired by BrokenOakleys, so if he uses a full round action, takes a -2 to hit and an AoO, he's gonna deal 3d8+1d4+9 damage. 25 on average...
CombatMartialArts and the Martial Artist build isn't really his style. He's a boxer, not a martial artist. He's not a bare-handed killer (well he is, but he takes a -4 penalty to hit when he does) -ninja.
I've built him as following (using a 42-point buy and two ability increases [lvl 4 & 8]):
Str 20
Dex 10
Con 18
Int 08
Wis 10
Cha 14
Strong 3; Streetwarrior 5.
Melee Smash 1&2 (he's a strong one!
)
Urban Survival (he's known and wellknown in urban/underworld environments)
Improvised Weapons (he's done some crazy stuff for the mafia - like killin' a barrister with a bathtub)
Street Cred (people from his area know him)
Improved Streetfighting (meh. he likes to punch people...)
Power Attack (...and real hard, too!)
Brawl (and Improved) (he's a boxer after all)
Streetfighting (he's a...you got the point)
Personal Firearms Proficiency (well.. Weapon Proficiency [autoloaders, smgs and rifles] to be precise - another houserule). (paranoid, wanted to protect himself from drive-by's etc. learned to use pistols and smgs. was in the army, learned rifle use)
Knockout Punch (and Improved). (autoexplanatory)
Renown (He's actually pretty wellknown indeed)
Light Armour Prof (...Army Flak Jacket)
This, as well as some flaws and traits from Unearthed Arcana, gives him +15/+10 on brawling stuff.
I'm considering replacing Power Attack with Combat Martial Arts, to allow him to threaten and not provoke AoOs, as that's pretty much the only thing that annoys me with the build. Any thoughts on/experience with mixing Brawl and CMA? If I end up givin' him CMA, I'll be sure to replace Renown with Combat Reflexes.