I've been doing some research for a podcast thing I'm gonna launch soon (watch this space!), and happened upon this.
It's the New Riders of the Purple Sage (with Jerry Garcia on pedal steel) doing a short, but sincere (the singer knows all the words..) version of "Fun Fun Fun", the night AFTER the Beach Boys did it at the Fillmore East. I'd categorize it as a tribute, not a mock.
(For the record, though I like some eras of the Dead a lot, and I like Nesmith's and Parsons' brand of country rock, I really can't stomach New Riders of the Purple Sage. Totally lifeless. Still, scroll down to Fun Fun Fun and enjoy the next minute and 10 seconds. They even get the change right on the chorus!).
http://archive.org/details/nrps1971-04-28.sbd.weiner.28176.sbeok.shnf