Treadstone, I went through the same process myself. I'm running a medium AirTop on an ARE CX shell with an internal frame and a couple of custom bars on top to make the tent more low profile. I've been really happy with the set-up I've got. Check out
this thread (post #4 and #8) for more details on my set-up. You might also check out
this thread for more discussion on mounting RTTs more generally. I definitely know people run Maggiolinas on standard toppers without issue.
Having said all that, if I had it to do over again, and knew I would be getting a RTT, I'd just get one of the reinforced toppers to begin with, like the SnugTop Sportsman or the Leer RCC.
ETA: As far as suspension, I went with OME all the way around and added the extra leaf (D29XL) to the Dakar pack. I've been mostly pleased with the results so far. Even fully loaded for a three-month trip, the truck rode and handled well. It's got a bit of a rake when unloaded, but I like that stance. My only two issues have been the leaf pack squeaking like a mother and the infamous Taco driver's side lean. I've added trim packers on the front, but they don't seem to make a difference for my fat @ss. And I've tried almost every lube known to man and can't get rid of the squeak. Not sure how to get rid of that problem. Also, I only got 885s up front since I have the stock bumper. If you're looking at the ARB, you'd want 886s, I think.