Naw, bad idea with some exceptions. When I first started in LF I camped with my dad using a custom cartop tent on a platform not unlike the one you're considering. I saw a photo of AA SUV cartop rig and realized the advantage of height. When I tried to take images with my first Linhof the slightest movement by me or the breezes caused frustration for any kind of long exposures. I quickly gave it up. But with a very stabile vehicle or some kind of bracing to remove weight from the springs and tires this might be feasible. I don't quite understand how Ansel was able to be successful using the technique though. I think it would be a hassle.