I've mixed finely diced onion into the sausage before, but never used it inside the roll. There's a whole pound of cooked bacon in there and if you add much more toppings it gets hard to roll. But yeah man, have fun with it, make it your own. I've tried making breakfast versions with hashbrowns and scrambled eggs, a meatloaf version using beef instead of the sausage, a pizza one with pizza sauce instead of bbq sauce.