Here's a simple solution to those who want their SACD/DVD-A surround channels to be placed more accurately: use bookshelf speakers that aren't bolted to the wall.
My surrounds are bookshelf speakers that are literally sitting on bookshelves, not fastened or bolted or whatever. When I feel like listening to a DVD-A or SACD, I pull 'em down and place them on stands that are a bit further back (roughly 120 degrees) and at ear level. And I move 'em back when I'm finished. Badda-boom, badda-bing, done.
cheers,
supervij