Gadler, I would quietly check the return/restocking policy of various suppliers. If it was reasonable, lets say 25% restock, and shipping was tolerable, I'd order the factory part. Its a wild-assed guess, but I believe there is a snowballs chance in heck it doesn't fit. If for some reason it won't you've a very close basic platform for any decent body shop to work with. You'd also earn the props of many, for I'm not too sure you're going to see enough market demand to justify R&D, production, and inventory stocking by the aftermarket anytime soon.
BTW, I too use a 1 1/4" bike rack on an adapter. It can rattle, but that's easily addressed. It also bought me some space away from the trunk/tailgate, and I was pretty happy w/that. Gotta watch weight though, because arm is real and it's applying a serious down force on the actual tongue weight/force.