Check out the timeline in the Chevron diesel FAQ and all your questions are answered:

http://www.chevron.com/products/prodserv/fuels/diesel/ulsd.shtml#A2

Going to ULSD caused the refiners to have to bring capacity off-line, refit and bring it back online. Then fuel had to be segregated in storage terminals, etc, etc.

As much as you're going to be paying at the pump for ULSD, you're going to be paying more when you start seeing it show up in dyed fuel stocks that you try to feed into 20+ year old fuel pumps.

The next time you see someone bragging about belonging to the Sierra Club, perhaps you might want to give them a piece of your mind.