You can get conversion kits that can make your truck a dually. I was thinking about customizing my old old Dakota that way. They have the hub adapaters, fenders and everything that you need. It's a rather simple process, really. I bet it looked weird!
My thing to do one day would get a F-350 Power Stroke, Standard Cab, Dually and get one big like, 18" wheel (wide) for the rear and one fat-*** tire. Drop that thing and make a 'sport' truck out of it. We all know that the'Stroker flies, imagine a light(er) one with a drop and non-dually tires/wheels. I think it would look kinda neat.
I am sure it has already been done, but I am not about to do a search, lol.
2010 SVT Raptor, Tuxedo Black -- 6.2 V8
2004 Mustang Mach1, Torch Red -- 4.6 4v V8 -- 5-speed -- way too many mods