The Band - Rock of Ages and The Last Waltz (ok, it's a triple)
Mountain Jam was originally released on the Allman Brother's next album (another double) Eat a Peach.
Another great Joni live double - Miles of Aisles
Likewise for Jaco (as part of Weather Report) - 8:30
Van Morrison - I'd take A Night in San Francisco over It's Too Late to Stop Now