What do you mean by a SHEAR Wall?
In-wall are only suitable for Wood Frame construction, and only in a house (etc...) that you own. As has been mentioned, if this is a Condo or similar, you have to check the rules. I suspect they would not allow something so drastic, especially something that intrudes on your neighbors so greatly.
You could potentially build a false or floating wall, which would not in any way effect the structural integrity. You simply build a full wall over the existing wall and mount the speakers in that.
Let me see if I can find a photo of a Floating Wall, these can be pretty cool. You build a smaller wall over the existing wall that is set out a bit. Typically people will install LED lights behind the edges that really makes it appear as if the wall is floating.
This particular one gives the Floating Wall effect, but it could easily be just a glorified equipment stand.
Notice on this one, it is quite thick and the equipment is built into the wall, again making it more of a free standing equipment stand than a true wall.
This would allow you minimal intrusion into the structural integrity of the existing walls, produces a nice impressive effect, provides a custom place to store your equipment, and gives you a place to mount In-Wall Speakers.
If the Condo board won't approve attaching such a system to existing walls, as I have pointed out, it would be possible to make it free-standing, un-attached to existing walls.
Though it may not suit you, this next photo at least illustrates the concept of a free standing wall -
To even understand the feasibility of this we would need to know the size (dimensions) of the room, and if possible a floor plan.
If the room is small, you might be able to sneak by with a floating wall. If the room is a bit larger, a free standing combination equipment cabinet and In-wall speaker placement might be possible.
A floating wall would have to be attached to the existing wall. But it would just be a few screw holes, and could easily be repaired when you move out, or the Floating wall could just be left in place for the next person. The Free-Standing is nothing more than a custom piece of furniture, and I don't see how they could possible refuse that as it is not really attached to anything.
Just a few thoughts.