I have Stella, Ranier, and North Star. I grafted these myself, many years ago. I remember, I got the Stella budwood, for the grafting, from the Canadian Agricultural Experimental Station, in Summerland, British Columbia. I think that's where they developed the variety.
Also, years ago, there was a place that I bought many trees from, (I'm in the nursery business) and they had very good quality. I Googled the name, and they're still around. I don't think they sell retail, but they have a list of dealers. The name is Dave Wilson Nursery
The DWN Backyard Orchard Culture Guide