Look up "Spring Shops" or "Automotive/truck suspension service" in your local yellow pages. FleetPride can make them up for you if you have one locally. It will be cheaper than if you order them. I usually pay $25 for a set of 4.
Summit racing, ask for The Rancho kit. A little pricey but good stuff. You may have to clean the holes out a touch to get them to fit.
RE are likely as good and maybe $20 cheaper, but Rancho is one of the best I've found. There cold plating seems to hold up well for years, little or no rust.
U-bolts sure aren't all created equal, some stretch, some are cold formed and prone to cracking. Cold formed and traditionally galvanized, used to be a disaster waiting to happen, but maybe they've worked out the bugs.
you should step up to a 9/16" from the stock 1/2". I think maybe the R.E. bolts are 9/16" but I'm not sure. Most off road & spring shops custom bend them from stock with rolled threads, much stronger than cut threads. mine were $7.50 ea including nuts & washers. D35 are 2.75" D44 & mopar are 3" width.