I know that Schreiner's bought out his collection, but they only seem to be offering a few.

My educated [?] guess would be that no one handles his whole collection. You will be lucky to find a few one place and a few another. There are so many introduced each year and it is regrettable that it doesn't take long for some nice ones to be forgotten.

Look around the garden listings in the PNW. they will appear in bits & pieces.