Petja,
I'm interested in seeing a photo posted of your setup. I, too, have been interested in doing a wall-mount. However, I'm settling for sitting the units on the brushed aluminum B&O cabinets until I find the time to do the wall-mounting. I would have preferred to see B&O continue with the oval design, but at least the materials and colors still complement the BC2 and the BS9000. I intentionally selected the two brushed aluminum B&O cabinets to have different heights and angles in order to play upon the contrast of the BS5 and BC2. I should think that a wall-mounted BS5 and BS9000 would look even nicer together.
With the BM5/BS5 being a computer and hard drive unit, it is inevitable that someday the hard drive will crash and the unit will need servicing. At least with two audio masters we will still have a backup music source during the servicing. Sad to already be thinking of a hard drive crash, but it WILL happen eventually.