Sorry for querying your memories, weelittledrummer, but the live double album by TH is one I haven't come across. As far as I know he did release a live album in 1968, though this was a single LP, and didn't have the song "Foggy Mountain Breakdown" on it. Maybe it was a concert bootleg? If so, he wouldn't have had any control over the final tracklisting. A lot of players seem to pick up the banjo for a song or so - Gillian Welch and kd lang, as recent examples I can think of.

There's a decent website on TH here