Recently there have been some lengthy clips posted on YouTube featuring James Brown's legendary performance at the Olympia in 1971. The quality is still pretty terrible, but this link is the first I've seen which seems to have the entire show. You don't want to miss "Give it Up or Turnit A Loose" at 43:43 and the closing medley of "Sex Machine/ Super Bad/ Get Up, Get Into It and Get Involved/ Soul Power" - the apex of Brown's melding of soul and funk. Bobby Byrd, Fred Wesley, Bootsy and Catfish Collins are all on the stage as the core of the JBs- one of the greatest bands ever assembled.
Though I don't think they're actually from the same show, the clips Olympia 1967 (part 1) and Olympia 1967 (part 2) feature some fantastic material with the Famous Flames, especially the 2nd link, which has decent sound and ends with a great version of "Please, Please, Please" and a riff of "Cold Sweat."
The entire show of the historic concert from the Boston Garden in 1968 (the night after the assassination of Martin Luther King, Jr.) is also online, but the quality is pretty poor.
Still, as nice as it is find this footage online, so far nothing beats the quality of the performance found on the T.A.M.I. Show dvd, so if you've never seen it, there it is.