Ooh, try the "maralurk" in Sandstorm (p. 170), whose LA of +1 is probably significantly too low. Small monstrous humanoid, 3 hit dice, but it gets, pretty amazingly, +3 natural armor, a +2d6 sneak attack ability, great ability adjustments (+2 Str, +6 Dex, +4 Con, +2 Wis, and +4 Cha)...