Did a quick search and found one reference but not much info. I have heard a JGB version of this song several times on the Dead Channel (XM) and it kicks my butt every time. Where is this from? It's obviously studio--OOAH girls and horns. It sounds to me like some producer decided "we're gonna make this guy a crooner". Might be the best I've ever heard Garcia sing, but it's such an anomaly. Who knows more...?
the movie 'smoke' If i recall. Yeah that is it. one of the last recordings.
edit: link---->
http://www.imdb.com/title/tt0114478/soundtrack
http://en.wikipedia.org/wiki/Smoke_%28film%29