I like this one the best out of all the rear bumpers so far. Too bad it won't allow you to keep the factory hitch.
edit: I just read that you also can't run your rear back up sensors...not sure if I'm liking this set up.
Too bad you're not in the LA area, that way you can just put one of mine on the 4 runner to test it out, but I truly believe they are identical. I know my buddy that's the parts manager at Northridge Toyota would know. They do mail-order too so it may be worth a call - his name is Evan Nikols...
these will fit your 4 runner no problem. And I think they look really good. I prefer to keep my mods as close to factory as possible, and with TRD they are factory. And I don't like the way that most aftermarket wheels stick out.
I'm sure if you are patient and look around you'll find some...