Magic Find solo thief build!
Acrobatics, acrobatics, and more acrobatics. Also, offhand pistol. Either dagger/pistol or sword/pistol. If the former, you want to take advantage of blackpowder, heartseeker combo to stealth, and backstab. If the latter, you want to take haste and shadowstep, blind with blackpowder, and go to town with pistol whip.
If you go to 25 acrobatics the minor trait gives you 10% bonus damage when endurance is not full, which, as you might imagine, combos really well with the Haste skill.