I'm not sure I understand why wide tires have to go with narrowed rearends. If you want a deep-dish wheel, yes you need to narrow the rearend to get that look. One problem I see is spring placement. To install a narrowed rearend you may need to move springs inboard, depending on what type of suspension the car has. How do you narrow this Camaro rearend?
I can understand wanting bigger factory tubs for larger tires but I think some muscle cars already allow for that. The Camaros have pretty big factory tires. The ZL-1 uses 11" rear wheels with a 305 tire, so the tub is already pretty big. It may handle an even bigger tire. I don't think the ZL-1 has unique tubs. How big do you want?