jims50,
it is really a matter of what you want. It is true that since the market for the 1/2 tons is much larger,you can buy just about everything for them. An example would be the brake drums. You can buy them for front and back new for the half ton but not for the larger trucks.
The cost of patch panels varies greatly among suppliers. You should get a pretty good idea from looking at two, say Jim Carter's and Chevy duty. Also, some are still selling the old repro version of the rocker panels which I don't believe have the correct shape at the front.