Jack if you have a spring shop in your area they can make you up a set pretty quick. Usually the heavy duty truck spring shops also re-arc car springs and have lots of the u-bolts on hand. I had my springs re-arced and an extra leaf installed, and also picked up the required u-bolts and lock nuts at McCoy Brothers in Edmonton and I think the whole deal cost me $110 CDN. This was before the price of metal took the last big jump so..... Also, the replacement u-bolts normally don't have the flat spot in the inside arch like the original Mopar ones do.
Sid