We have some good sponsors in the links above. All Pro carries gears and lockers for Tacomas. TRD parts 4U (which is Toyota of Dallas) has always given me big discounts off of list price, but I've never bought aftermarket stuff from them even though I know they carry various brands. For gear sets...Yukon is good and usually available.

Outside of our sponsors, I'd try Randy's Ring and Pinion or Performance Off Road Center


Wheeling a Stepside Tacoma on 37s
Exploring in a T4R Ltd V8