The dual alternator set up was an option. But as far as it being any better? Who knows. But i do know that is is very cost prohibitive to add it on after the fact. One would need brackets, both alternators, different belt, new wiring loom, pcm, etc. There is a alternator shop that i have dealt with in the past. They can take a stock alternator and rewind it for higher output. That way all that may be needed would be a different belt, if the pulley size was changed. And they also rewind starters for high compression engines, etc.
I have never heard of any wreckers or transporters having dual setup. It seems that it would just be more trouble. But maybe not. I wore out 2 stock alts. in the first 100,000 miles on this truck. I have 98,000 on the 150 amp out of Johnson City TN. Electronics via EBAY. On my 2002 f350 7.3 I went through 4 alts in 300,000. This included a rebuilt Auto zone one that a certain sorry ass cheatin Ford dealer in Atlanta Texas snuck on. He only charged me $440.00 to do it. It lasted all the way to Arkadelphia AR. About 100 miles. The Ford dealer there put one on for $390.00 and it is still on and working. I watched the dik hed wrench twister in Atlanta put the alternator on. When he tested it with his bright orange digital Blue Point MultiTester ( I have one to), He told me the reason it was only putting out 11 volts is because the batteries were low and it would increase as they charged. The Mechanic in Arkadelphia told me it should have read 13.8 or higher because the batteries were low. If I had had a second alternator. I might have been able to make it home to Memphis.