Another thing you may want to check out seeing as how changing the hubs is very expensive: Ford made a 5 bolt 16" rim in the 70's for a half ton (1976, I believe). These rims are very rare, but not particularly valuable. I used to have two of them, but I got rid of them in my last shop clean-up. Anyway, I am not sure if the bolt pattern would match up or not, but the ford/dodge 5 bolt pattern is a very common one. FWIW.
Dave