Opinions and ideas all welcome!
You want someone who likes to fight, has no moral and will do practically anything for money. I would go with Vorstag.
I'd also go with Benor or Vorstag, or maybe even Stenvar. They're all completely cut-throat.
He's lawful, though. Bronn admits that he'd slice up a pregnant woman's belly, if the coin was sufficient.
There aren't many more amoral, non-magic using sellswords in the game besides the ones mentioned. There's Jenassa, but she's... a she. If that could be ignored, she'd be very much like Bronn.
Teldryn is a perfect match, although hes a dunmer.
I know he was given the No Crimes moral, but let's be frank, he doesn't give off a lawful vibe in the game.
Benor on the other hand? He definitely does. Actively assisting the town guard of Morthal and doing it for free.
Not entirely for free... he gets to sleep in the guardhouse at night.
Put 500 coins in his purse, though, and he'll do whatever you want him to.
I killed him for Boethia, sorry Benor but needs must