Let me kick off the Epimedium 2013 topic here in January, by highlighting some nursery sources. Choice Epimedium are becoming more available, and prices are starting to come down (although depends on where you shop). I have started the following list, please feel free to add links to additional nursery resources, indicating where the nursery is located.
Garden Vision Epimediums - Massachusetts, USA
"The Source" for extensive offering of accurately named Epimedium, including many of their own offerings by Epimedium guru Darrell Probst, now operated by Karen Perkins proprietor. No true interactive website other than an old photo gallery at: http://home.earthlink.net/~darrellpro/
Contact Karen Perkins at firstname.lastname@example.org and request a catalog, instead of using the contact link on the photo gallery page. In May there vare two "open nursery weekends", not to be missed.
Free Spirit Nursery - British Columbia, Canada
Epimedium introductions, 'Atlas', 'Spring Hearts', 'Spring Chocolate'
Thimble Farms Nursery - British Columbia, Canada, they do ship to the US.
Excellent affordable list of Epimedium, including the new 'Atlas' from Free Spirit Nursury.
Lazy S'S Farm - Virginia, USA
Pretty good listing of Epimedium, some choice items and good pricing
Collector's Nursery - Washington, USA
Very good listing of Epimedium, many of their own hybrids, fair prices.
Plant Delights Nursery - North Carolina, USA
Very good listing of Epimedium, many of their own hybrids, prices on the high side.
It should be noted, that on some of the nursery lists I have looked at, there are a few misnomers/mis-IDs, where the photo does not match the species or cultivar. Be sure to research to make sure you're getting the right thing.