Here are a few article and papers about the Saskatraz bee line developed in Canada. It appears this beeline is varroa mite tolerant without use of any chemicals. Reading of the second paper below seems to indicate this beeline is similar to the Purdue Ankle Biter beeline in that the bees bite off varroa legs.
I see that Olivarez Honey Bee, Inc. is now selling this variety for $32 each plus shipping. After trying to order a few I was informed that their website for ordering queens via the web is not yet operational, but should be in a few weeks. They are NOT accepting phone orders yet.