I recall Mr. Harris saying that there was some way to produce an acceptable blu-ray of the extended version from what MGM had. I don't think he ever detailed what he had in mind, although he thought the general release version needed full restoration.
Not that it means anything, but when I go to the Alamo page at Kochfilms.de linked above, the next title linked to it is a special edition of The Long Goodbye, which Kino has promised to release with an updated transfer.