How exactly do you plan on putting an amplifier on a speaker in the ceiling?
This really goes against anything I've ever heard of. Bluetooth is a continuously evolving technology, and likely will have a new/replaced version that makes the current version obsolete in several years (or so).
The issue then is that you need power (high voltage) into a back box of a speaker with integrated electronics, and all of that needs some sort of UL rating for the power connectivity in the ceiling.
Yes, there are a couple of options I imagine. I found this set, for a fair bit of coin, and some crazy cruddy speakers:
https://www.kbsound.com/products/bluetooth-in-ceiling-speaker-select-2?utm_medium=cpc&utm_source=googlepla&variant=20043274822&gclid=CjwKEAiAvs7CBRC24rao6bGCoiASJABaCt5Dv7gx8_hr7cKcXy_dxUUoGQNESMxghCmj_JGdCQzdMxoCqqPw_wcB
But, typically it is better to use a simple Bluetooth speaker sitting on a shelf, or put some decent in ceiling speakers in then run it to a Sonos Connect-AMP, or to a small Bluetooth receiver/amplifier like this:
https://www.amazon.com/Bluetooth-Audio-Receiver-Amplifier-Model/dp/B00JB4YWGO/ref=sr_1_5?ie=UTF8&qid=1481927388&sr=8-5&keywords=bluetooth+home+amplifier
While illegal (against NEC), you could put that small Bluetooth receiver/amplifier in your ceiling and run the speaker wire to a couple of in ceiling speakers. If I was determined, I might do something like this, but you still have to get power to that unit, and I'm not sure how you plan to do that if you can't run speaker wires to begin with.
Oh, and Bluetooth pairing almost always requires a physical button push right on the device itself, which is not exactly convenient with in-ceiling speakers.
