Since Hollingsworth's offered Quitzen I'm hoping they will offer more in the future, also the Peony Shop could be a source. He does some amazing work! Looks like most were introduced in the last 6 years with just Quitzen and Sumvitg a decade older. That's a lot of new introductions in a short time.
I did get Quitzen this fall and I have Lemon Chiffon, both are parents of some of those seedlings. Looks like I need to attempt a cross-pollination!