Welcome to the land of lost roof caps. Your best bet is hitting junk yards on a day off. Put your pride aside and go hunting. I scored one in great condition (it broke upon removal, since then it's been super glued and Bedlined so it's never coming off again) I personally like the stock roof rack look and don't have any intentions of changing it anytime soon so I'm happy with my setup. Just be careful when removing them they're pretty fragile.
Dont give the stealership the satisfaction of buying one new.