I was looking for the same thing last year for my garden in Chandler, AZ and settled on NuMex Casper. I planted seeds 10/15/15, and harvested 6/19/16. So far, it is storing well, at almost the 3 month mark. Technically, it's an intermediate-day variety. I believe it was bred to be seeded February 1 in the Las Cruces area, but the fall seeding worked for me better than the February 1 date. As for taste, it's not the sweetest white onion I've ever tasted, but it's not pungent either, and you can eat it raw with no "breath issues." Overall, I think it's a good compromise between sweetness and storage. Here's what the NE Seed online catalog has to say about Casper: NuMex Casper stores well and is great for production in Mexico. NuMex Casper is an intermediate day white onion that has proven itself over years of commercial use. This jumbo-sized onion variety features attractive round to Grano shaped bulbs with clear white skin and crisp white flesh. Tolerance to Pink Root.
