Mark's French cleat (that's Francais for "camel toe," I think)
is pretty close to a wall slat system. Just flip the top board around and your reveal is a sliding dovetail.

If one were satisfied with inelegant for set up, it wouldn't be that difficult to whip somthing together, then permanently place speakers where you liked best. A couple of hd fully articulating ball joints, etc.

The remote part's a bitch----servos, relays, 12v power...
Have you checked out the international slave trade lately?

Always call the place you live a house. When you're old, everyone else will call it a home.