I've done some more digging on the web, and I think I may have found the answer to my question (i.e., who has recently re-recorded Mary McCaslin's "Circle of Friends"?)

The song's refrain (in part):

"But you just go round and round in your circle of friends. Ah, yes, our circle of friends You know how a circle never ends ..."

Cris Williamson recorded a live album entitled "Circle of Friends" in 1991, with a song listed of the same name. Again, as a folk novice, I don't know Cris' work. I found this listing at an online music store, and the track isn't available to sample, so I can't listen and be sure.

Still, the recording for which I am searching is in fact of a live performance, and a sample of a different song of hers sounds very much like the "mystery voice." Can someone confirm my hypothesis that this is, in fact, the same song? I'd be most grateful.

Thanks

Dave