I found a 5-gallon jug of Royal Purple HPS 5W-30 for pretty cheap ($130) on this site called autoplicity... Havent used it yet but have heard good things...
After reveiwing the first link posted in this thread, someone brought to my attention....
Amsoil OE 5W-30 is only $94.00 for 20 quarts of oil at preferred customer pricing, and it's on the same level (if not better) than the base Royal Purple oil.