Have you tried these yet? They're part of the Rancho Gordo-Xoxoc Project and they're that rare bean that makes you sit up and take notice the minute you taste them.
Even though they come from Mexico, when cooked with mirepoix and olive oil, you would swear you're in Tuscany. You can replace any small white bean and come out a winner. I think they're even better than the elusuve Zolfino bean. Try a classic fagioli all'uccelletto and I think you'll be hooked, too.