I think I've seen them once or twice in midwest (but outside chicago) grocery stores. I think I may have even once bought a package of their natural casing hot dogs (lamb casing) which were fine, but nothing special.
For what it's worth, one of the Vienna Beef owners is an Eisenberg. Somehow I bet they're related...
edit: a little more research shows they're partnered with kelly corned beef co.
http://www.kellyeisenberg.com for an incredibly useless website.
-ed