Here are 3 good sites for info. I have never ordered from these people but they do have good info...good descriptions of many heirlooms.
http://www.reimerseeds.com/tomato_711.aspx
http://tomatofest.com/heirloom_tomato_seed_home.html
http://www.heirloomtomatoplants.com/
Black Krim sounds like a good one. I found some plants at HEB in Austin so am trying them for the 1st time...
Thanks. I have bought some from Reimer before. They had a hard to find variety that I wanted, plus they sell small quantities. We have a very small garden plot, so we dont need large amounts of seeds. I keep unused seeds in the freezer. I didn’t even have to buy any last year, nor this year.