I had Real Wheels build me some double Beadlock 16x16 8 Stud Alloy - Nice job and price. Don't worry about the stated sizes on the site. They will make any size you require http://www.realwheel.net/products.php?catid=12
I had Intro build my 20x15 8 stud Alloy that are on rear of my red truck - Nice job and price. Don't take too much notice of the sizes on the site. They will make any size you require http://www.introwheels.com/hd8_1.shtml
summit racing has 15" wheels on an 8lug pattern if you just need them for the rear i know you can grind just a little meat off the caliper and they fit. not sure if you need to put them on the fronts too though.