I think you have all the facts exactly correct, and I think, with the right conditions, the chances of some of the cold-hardier cultivars surviving your winters and doing well is very very good. One thing I'd add is to be sure to give them good drainage. Maybe plant them in a slightly raised bed if you don't have really good drainage.

There are many sources for mail-ordering artichoke seeds (most vegetable seed catalogs). I've seen the plants offered, but I'm not sure where right off the top of my head.

I'm in Nashville and starting artichokes this year. I have them in a south-facing raised bed that is usually covered with plastic during the winter.

I was curious about how yours are doing, tcalahan.