Ebay is your only option, EBMM will not sell them seperately. The closest you can buy are a Dimarzio Tone Zone for the bridge and a Dimarzio Air Norton for the Neck.
Tim is correct. And by my experience, the Air Norton & Tone Zone are not very similar to the EVH pickups. They're the same category of high output pickups, but they sound considerably different.
That's a little discouraging since DiMarzio says these are the closest production pickups to the EVH/Axis pickups they make.
I have a quicksilver guitar from ed roman guitars which uses seymour duncan black back pickups. I also have a music man axis. I swear to you these pickups are identical. I know one is dimarzio and one is seymour duncan. After reading an article on ed roman's website I believe that these pickups are the same design just made by different manufacturers. To my ear they are almost identical..you read the article and see what you think. You can purchase these on his website too. http://www.edroman.com/parts/blackback.htm