Mont Alto's excellent edition of THE GENERAL includes a pretty good commentary:
Recordings
From my review at digitallyobsessed.com:
"Mont Alto offers one of the finest prints I've seen of The General, one of Buster Keaton's best pictures, with a thoughtful score in an excellent transfer. This beautiful, easily-overlooked package is very highly recommended. No reason to hesitate."
Mont Alto also releasing MARK OF ZORRO shortly; I haven't watched it yet though I do have a review copy, which indicates it's from the same source as the forthcoming Flicker Alley release, but before DNR was applied, and it also has a commentary.