Enough room for 15x10 on a Demon?

You're going to need to mini tub it to get a 15 x 10 otherwise they'll be hanging out the wheel lip. Don't limit yourself to 4" bolt pattern - your wheel choices will be limited. But you have to upgrade the axles and brakes to do it. Or a 8.8 Explorer or rear out of a Ford Maverick/Comet.