Following on from a suggestion from Mat re full length Video of complete works both jazz and classical I will start the ball rolling for the Classical with a couple of Mahler Video.
Sym #1 with the New York Phil, Lorin Maazel this has a length of 0:54:13
Sym #5 C# min Chicago Sym Orch, Barenboim @ 1:15:20
Please add your finds with details lets see what we come up with
Both of these look good on the big flat screen TV