After all the years of these questions on the Peavey forum, I guess i am a bit jaded to the whole "Edward" thing.
His red/white/black pattern is copywrited, and he has been known to sue people who copy it.
As too a combo, there are always a couple of them on e-bay.
Hold on a second-I have to go find my head 'cause some one just chewed it off-JEEZ! Anyways, I am unaware if you visit Youtube much but I saw a clip of a 5150 III at the 2010 NAMM show that had the red, white and black covering on it in the FENDER booth, not the Peavey booth. Secondly. Why would you think I would go to the Peavey forums to look for the answer since it now made by FENDER. Lastly, virtually every amp company that make a stadium duty amp also makes a few smaller. lighter duty amps in the same class which would most likely be engineered at he same time. They would probably sell 6 $ 1,200 amps for every 1 $ 3,100 amp but that's just common sense talking.
I am sorry if I was a bit too abrupt with my overly flip answer.
Edward now has his amps made by Fender, you are quire correct, I , II or III, they all sound pretty much the same (Assuming you add a trim pot to properly set the tube bias).
So Peavey made the 5150 combo for many years and they can be found on e-bay and in the used market.
If you want a new one, they are still being made under the "6505" and they run 1199.00 new.
So why would Fender go and tool up to make yet another 3,100.00 dollar amp when you could by 3 Peavey amps for that muck that sound the same?
BTW, Peavey made those red/white and black guitars and amps for Edward, but they could not make them for sale to the public.
Marriage is like playing cards...
At first all you want are Hearts and Diamonds.
But in the end, all you really want is a Club and a Spade.