15" 8 lug wheels aren't too hard to find, I have a couple sets of 10s for my Blazer. Good value is the American Racing White spokes, mine were $36 each from Discount Tire 5 years ago. Jordan Kloppe had a set of 15" slicks on his at the drags a couple months ago, he had to slightly modify the fins on the brakes to make them fit. Standard backspacing for this size is 4 1/8", you can get them with less. Both of my sets are 4 1/8", and they cleared the stock drum brakes on 3/4 and 1 ton 14 bolts fine. Might trial fit them before you buy.
Pete