The OP specified "multi-LP" live albums, yet most suggested here are single-LP albums. 1975's Frampton Comes Alive made multi-LP live albums more commonplace, very few previously having been recorded and released. Of those that were, my faves are The Band: Rock Of Ages, Dylan/The Band: Before The Flood, and Derek & The Dominos: In Concert.
By the way, Rock Of Ages is an abbreviated release of the recordings The Band made at The Academy Of Music on December 30th and 31st of 1971.. An expanded release containing both complete shows was years later made available as a 4-CD/1-DVD boxset entitled Live At The Academy Of Music 1971. I had seen and heard The Band the previous year at The Berkeley Community Theater, a night of music unlike any other in my life.
