These could either be reissues that were announced and went unreleased or something you'd just like to see happen.
Pink Floyd - Atom Heart Mother Immersion Edition This would include the most recent remix/ remaster, the original mix, the discrete Quadraphonic mix only issued in the UK and two live TV specials from 1970 featuring material from Atom Heart Mother, one taped for French television, the other for KQED (PBS San Francisco.)
The Beach Boys - Surf's Up DVD-Audio edition. This was announced but never released. 1971's Surf's Up was an early Quadraphonic release and I'd like to see this reissue include that mix plus a new 5.1 remix, a documentary and the songs Dennis Wilson was going to contribute to the album but were left off last minute due to a falling out between him and his brother and fellow band member Carl.