Thanks to the good recommendations on this forum, I went to the Rancho Gordo site last week and ordered three bags of heirloom dry beans - white tepary, flageolets and cannellini. They arrived Thursday, one week to the day after I ordered, which struck me as just a little slow for an $8 flat-rate shipping charge, although in fairness they were right on their estimated arrival for DHL Ground.
The beans all looked great, and I was especially impressed with the cannellini, which are the size and shape of very large white lima beans. So today, a pleasantly cool late spring morning, I made a batch of Tuscan beans, following the soaking and simmering recommendations listed under "Rancho Gordo method" on the rather generic card that came with the legumes: Soak four to six hours (I let it go close to six, being a little suspicious that they didn't have you go overnight), and simmer one to three hours, adding no acidic ingredients or salt until after cooking to avoid toughening.
At that point I went over to an old traditional Tuscan recipe - simmer with a half onion and several sprigs of fresh sage, salting after they're tender and seasoning with ripe, green olive oil and black pepper when served.
I got a little nervous when the beans were still hard and raw after 90 minutes, but just about on the three-hour point they just suddenly snapped to al dente, then beautifully creamy, infused with onion and sage flavors. In short, they were absolutely outstanding, as good as any beans I've ever eaten - and I've made this dish many times before, usually with Great Northern or navy beans or cannellini more the size of Great Northerns. These were better.
Nitpicks: I'd love it if Rancho Gordo sent more detailed information along with each bean variety - it would have been useful to know that the big cannellini were going to take the full three hours, although in retrospect I might have figured that out based on their size.
But, bottom line, these were incredibly good, and I love it that Rancho Gordo has so many different bean types and varieties, including European beans, American heirlooms and even really unusual Southwestern American Indian indigenous varieties like the teparies. I can't wait to try the other bags I purchased, and I'll definitely be going back for more.