Jack in the Box sold Frings for a short period of time once when I was a kid. Basically it was half an order of fries and half an order of onion rings put together in a special two-compartmented version of those cardboard sleeve things they normally sell fries in. I thought, hey, cool idea (hey, I was a kid at the time), but then a while later they stopped selling them.
Not that this was a big tragedy, of course; they still sold fries and onion rings, and all you had to do was get one order of each and split them with a friend.