I am on the rebuild, from moving away from my old nursery about five years ago. The next shrub I'm on hunt for is a rhododenron fastigiatum, its just a little shrub. but seems like everybody who has it on offer is in Britain. I cannot import from there. My source(s) must be inside the USA. If you know of a USAin source, please share it with me.
I've tried looking at this end for you but have had no luck. Every supplier that I've managed to find is UK based too. I find it strange that this is the case though as the plant itself isn't all that expensive. All I can advise is to see if any of the suppliers here would be willing to ship to the USA. I think that the P&P could prove rather prohibitive though.