Need Advice on Surround Speakers for my System...

Hopefully, this is the last piece of audio that will finally complete my system. I've been buying/selling on for the last 2 years striving for the ultimate sound at a reasonable cost. I think I am finally there. I recently sold my rear channels (They were B&W Matrix 805's) due to size. Now, I need a replacement. I prefer speakers that can be hung on the wall. The only one that I've been real interested in is the B&W DS6. Any Suggestions are appreciated...

My System:
Source: Mark Levinson No.37 Transport
Mark Levinson No.36s Processor
Denon DVD 5000
Pre Amp: Proceed AVP-S
Amps : Mark Levinson No. 331
Proceed AMP-3
Spkrs : B&W Matrix 802 II w/ Sound Anchors
Spkr : B&W Nautilus HTM2
Spkr : ????????????????????
Sub : PSB Subsonic 2i
You will be disappointed with the DS6... it isn't a full range speaker (rolls off at around 16k). I tried it out and returned it. You might want to consider the SCM1. It is the Nautilus replacement of the SCM8 which matched the Matrix 800 series. It is a shallow cabinet Nautilus 805 and can be mounted on the wall.
Both Vienna Acoustics and Linn also make a good rear speaker w/shallow cabinet that can be mounted on the wall. I esp. liked the vienna acoustics model, I can't remember the model name right now.
I have tried several rear surround speakers to go with my Vandersteen 3A Signature main speakers and Vandy VCC-1 Signature center channel. The speakers I've used include the Vandersteen VSM-1's (wall mount); Coincident Triumph Signatures (on stands); and the M&K SS-150 THX tripoles (wall mount). In my audio/HT room, the speakers must be mounted behind the listener. Given this requirement for the surround speakers, I liked the M&K's the best and have kept them in my system.

The other wall-mount speaker which I auditioned and liked very much is Snell's relatively new tripole surround. At $1500 a pair, they aren't cheap, but they are very well made and struck me as excellent surround speakers.