I have a 78 as well, doing the same upgrades as well except the bags. As far as control arms Little Shop Manufacturing makes a uppr tubalar. For lowers I dont belive there are any but Rare Parts reproduces the lowers. I have a set of those and quality is nice. They sell fast, if out of stock call them and they will give you a production date. I cant recall if you can order and be on a backorder list, they are good to work with. They also have some other hard to find items for 77-79's. As you are doing a frame off, what are you using for body bushings?