I would try a ranger(11)/rouge(9) as a start. Wood elf or human probably. Maxed out str, some dex (no more bonuses than your choice of armor can handle +4 for chain shirt if I recall correctly or try mithral forged medium armor), rest on con.
The main reason of the ranger is if you specialize on dual weapon style, you get all three levels for free, and do not have to have 19 dex, which is imho rather useless anyway.
Probably you should wield short swords or kukris, actually the same weapon in your both hands, since you will not have enough feats to get focus/imp. crit/power crit for different weapons.
Or go brutal with a half orc
For this build the +1 attack of your off hand given by ranger(11) is crucial, since you have 5d6 sneak attack, and if you tank with one of your party member, it matters really.