A System 11 (Rollergames) will just fit in a 2007 Jeep Grand Cherokee. Head folded down, back in first. The issue is getting it through the hatch. It's super tight on height, but it will go. Lifting the folded-down back seats just a little as you slide it in will help it move over the seat hinges. Using some cardboard or the like could also make that easier.
Other than the hatch, there's plenty of room.