I'm surprised that nobody has mentioned Hallson Gardens.
http://www.perennialnursery.co...
Chris, one of the owners, is one of the most knowledgeable people around when it comes to HVX. I've not been able to purchase from them as I live in Canada, but I've seen postings of the size of plant people have received and it's generous. BTW, Chris also runs a garden chat list which has a number of people who know a lot about hostas participating.
