How to get multichannel sound from a CD?

I was at a friend's place recently and heard him play CDs through his new Linar multichannel amp, which has the ability to direct part of the stereo signal to the back speakers. The effect was surprisingly good: spatiality and power increased, without any apparent damage to sound quality (as long as the rears were not too loud!).

This got me thinking: Rather than wait forever for the major labels to start releasing good quality multichannel recordings in SACD or DVD-A, why not explore ways to get extra spatiality out of my existing large CD collection?

So I'm looking to find out what options exist for doing this. I'm just gathering info at this point, so any tips you have are of interest--a bonus would be your comments on how good it sounds, but just hearing about an option is good too.

Note that I do care very much about sound quality issues such as timbre, tonality, musicality. The best options for converting CD to multichannel will do minimal/no damage to essential sound quality, but will add spatiality.

So far I know about the following:
-The Linar amps, and maybe other multichannel amps, that just direct the sound to the back
-the Meridian 861 processor has a mode for this. Super expensive, supposed to be good.
-the McCormack universal player has a mode also. Stereophile seemed to like it a bit less than the Meridian for this purpose, but it costs a lot less.
-I think DTS has a processing mode in some receivers which can do this (I'm not much of a home theater guy, no receiver in my system, so I'm sure many of you will know more than I about this).

Any others you guys know about?