Let's examine this idea a bit.....
the W2, 3 and 22 are designed to mount vertically, and may be possible to c'sink somewhat in the wall, provided you locate them between two studs. You will still need to come up with an alternative mounting method then the stock clamping frame.
The center speakers, conversely, are designed to mount horizontally and will present a much more diffcult install challenge. Standard wall stud spacing is 16" on center, which is likely what they were designed for if you notice the width of the rear enclosure.
Considering the intended application, i.e. use with flat panel LCD and Plasma TV's, the projection from the wall is probably no worse than said TV's.
