The forum has a 'sticky' thread with a list of recommended vendors.
The thread "Vendor list" in
Irises forum
I have used Local Harvest vendors in the past, but I don't know that there is any kind of pre-sales vetting process to determine if a vendor is reliable
mamajack is selling a mixed lot of Bearded Iris on Cubits from her place @ 30 rhizomes for $19 shipping included. She is a friend of mine and I took photographs this Spring of the ones she is selling when they were in bloom. No guarantee of which ones you will get, but, friendship aside, I know she is reliable. If you look at the thread, you will see several ATP member IDs to ask them--in case I come across as a shill for her.
http://cubits.org/notfortheser...
Some of the ones she is digging up:
