Archaeologist archetype for bards? Basically just rogue flavored with magic and shields, but the language looks vague enough that it gives half your bard levels to perception in general instead of just traps. Could be useful. More of a face of course, but again, you wanted to be more handy for your party, no?
Meh, I've never seen any trapper build worth it's salt; it's basically a novelty gimmick with no real in-game applications. At least not if you want someone able to trap effectively in combat. The best 'trap' I can think of is an alchemist with various bomb discoveries. I believe that there's one that has delayed blast bombs, which could make for some fairly potent traps. Add in the variety of additional effects that can be added to bombs, and that's way more efficient than any 'trapper' build I've seen.
Depending on the level of the game, you could also have fun with Symbol spells and Glyphs of Warding.