I'm interested as well. From my research "day nuetrals" or "medium day" are said to do well here in addition to "short day" types. As much as I love the granex types (I eat them raw for a snack) they don't keep worth a dern. Being an onion and garlic lover and user (5-10 pounds a week) a storage onion would be perfect. (I don't mind my onions having flavor either)

Unfortunately, Atlanta is not "keeper onion" country!!! I've been speaking to some organic farmers about onions. They grow fairly small here, organically - and yes, you need to grow as mcleod says... however, I've been growing them and then chopping and freezing to save them.
I also grow perennial onions which store right in the ground!
Potato onions, multiplier onions, welsh onions, shallots. As many different types as I can find.

Girlgroup, tell me all about your perenials. I've never grown perenials. Always have been sets granex and bermudas and those get used as fast as they come out of the ground which ain't long enough around here.
I really like the idea of in ground storage and being able to pull and use as needed. Size, flavor recommended varieties please.

Well, potato onions are the largest. They aren't large, and you just take what you need. They grow in a group, and grow by division. I harvest green tops when needed, and they grow back. Bulbs when needed. You always need to leave some untouched so they multiply. In general they are just called "Potato Onions". You get what you get when you order.
I have topset onions, which are slightly larger in the bulb than a green onion. Again, I use tops and then the bulbs and they are very strongly flavored, so one or two onions in a dish is fine. There are several kinds of these under various names. All are heirlooms and probably each has several names...I have some "red" and some white (the color of the bulbs). In June the greens grow thickly and tall, flower and then set into bulbils (not seed) which fall over and root and then you get more onions. Right now is their most active growth period.

These like VERY VERY rich soil which drains well and I find do best in afternoon shade. Mine in full sun, good (but not super rich) soil with less moisture tend to go into dormancy and not be so nice in July and August. Those that grow in our church garden in excellent soil, good drainge and afternoon shade look fantastic all year. And they will multiply quickly! My goal is a dedicated allium bed.
The Welsh onions are sprinkled around my organic flower bed and I let them self seed.
You can get many varieties of the onions through the Southern Exposure Seed Exchange and from Fedco (and probably other places)