my understanding is that most, if not all, aftermarket wheels are made so that they can be lug centric - you know, more of a universal application thing.
The Dodges do have a larger hub than the GM, so yes, Hummer wheels have to be clearanced in order to fit on the Dodge. I doubt there are many, if any, aftermarket wheels that are only going to be able to fit the GM application and not the Dodge also. Having to make the wheels with two different center bore dimensions for the hubs to go through would kind of be shooting the wheel manufacturer in the foot don't ya think? While there may be some, I'ce venture to guess that most will fit the Dodges, and therefore have adequate hub clearance to fit the GM applications as well.
C-ya