In-Ceiling Speakers - No amp

 Big untapped opportunity  - 6” in-ceiling wireless Sonos speakers next to 6” Hue LED Downlighsts would blend perfectly and the Sonos’ could be tap into existing constant 120v lighting power lines since the Hues dim wirelessly at the bulb level. 

I’d assume product managers at Sonos are watching the potential market fairly carefully, but as of yet, this untapped market hasn’t been enough to have them design a speaker, and set up a production line, both I would expect to be relatively expensive, alongside their current lines. Which means a minimum amount of sales to at least cover the costs. 

This is where smaller companies have an advantage. Tighter focus, less overhead means profitability in a smaller market. 

Seems the technology exists.  Maybe I’m thinking too simplistic, but take a current in-ceiling speaker and bolt on the wireless capability plus the hard wired option mentioned by @mclark.

Really pretty easy to stick an Amp above the ceiling, many unobtrusive access panels.

Long term that would likely be less aggravation as the Amp would be easy to access if needed while the speakers would both have to be dismounted or at least the covers removed if the controls are available from the front.

If there is a closet above the planned speaker location you could place AMP in the closet and run speaker wires through the floor, into the ceiling.

Placing AMP inside the ceiling will be against local building codes in many areas -- unless you use a special enclosure that will not be very attractive.