Check this link out:
http://interprod.imgusa.com/son-403/i_Searchpage.asp
It has a pretty cool listing of classical SACD's. I'm not sure what your exact criteria would be, but the ones that I would pick up are:
Leonard Bernstein, NYPO, Gershwin - Rhapsody in Blue, An American in Paris, etc.
Glenn Gould, Bach - Goldberg Variations (his later, 80's recording of it)
Igor Stravinsky, Columbia Symphony Orchestra, Rite of Spring, Firebird Suite
Bruno Walter, Beethoven - 6th Symphony
All these are single layer stereo, though (no multichannel, can only be played on SACD player). Maybe someone else can recommend a really good multichannel recording...