Theres a couple ways, mines done with a 3.5" inner spacer, a dodge dual wheel, then a 2" spacer, then an american eagle dually wheel on the outside. I had to grind on the calipers just a bit, i think if you go with 17"s you dont have to grind any. Also i run 35x12.50s, with narrower tires you wouldnt have to go with so big of spacers.
Also Tony Burkhardt from All Seasons Service sells a spacer than you can dual up H2 wheels.