You should do a sick burnout while there is no weight over the rear axle.
Hell I can do that with my 87 Ranger long bed with the bed on it...there's very little weight back there so in the slightest of low traction conditions you can spin the tires all you want, also doesn't help that is a 4x2 LOL. I kind of want to put a limited slip or locker in my Ranger but with no weight in the ass end I don't think a limited slip or locker would be of much use either...just need to put about 4-500 pounds in the bed and leave it there for the winter.
Not sure how useful a flatbed would be for some, but there's times I wish I had a flatbed, especially if I need to haul something large and/or heavy being able to simply slide it on and off the bed would be nice at times, or for hauling hay a flatbed would be useful. Have it built with pockets so you can build sides for it for the times you want to haul stuff and not have it slide off the bed...oh like maybe your dog not flying off the truck bed like I see happen here in Idaho a lot.