Nope, none, zippo.... sorry no headers for either the 4th gen 4runners or the gx series.
Won't happen for ALONG time unfortunately. Problem with it is the design of the headers themselves. Someone can make them but the location of the cats are too close to the exhaust manifolds that making headers won't do much unless you move the cats back or something. Moving the cat's original location means getting BAR approval which means $$ for the manufacturer...
just sux for us I suppose.