The only way I can see to have a race legal roll bar for a driver of normal stature is to have the main hoop back against the rear bulkhead and to have braces from the top of the hoop, going through the trunk area to plates underneath it. Few drivers would be willing to be unable to put up their tops, or to limit use of the trunk. This is a problem with all sports cars that have a tonneau panel (that's what it is called, technically) immediately behind the seats - there is not enough space to mount braces at the required angle. Braces to the front, are often not allowed as primary braces, but even if they are they have rather obvious disadvantages as far as utility is concerned.
Good point about the Jeep - impacts are likely to be fairly low compared to race cars. Last roll over I saw at the track was at better than 80 mph and the car flipped three times before landing on it's roof!