Re: best source for Sonance in-ceiling speakers for ATMOS
I'm not sure about the white grille - you'd need to ask Dave/Dina. I think I may have done so several years ago and it was possible, but not cheap.
As to mounted in the ceiling, I think if there is the depth between the face of the ceiling and what's above it, and space enough between the joists, it would be possible to mount them flush. I recall a post from a few years ago that someone did this. As I recall, they used the existing mount holes in the cabinet and also put one or two studs on the opposite end, and bolted/screwed everything to whatever was above. If I had mounted them to the ceiling in my room, that's how I would have done them (I'm in a single story, so would have bolted to the flooring in the attic above). That said, I would have mounted the cabinet backs to the ceiling so they hung down and not cut holes into the ceiling/attic although the ceiling does also have "can" lights which protrude into the attic.
* LG OLED65E6P, BenqHT2050A
* Anthem AVM90, Rogue ST100, VTV Pascal 7 ch
* Sierra Towers/Horizon (all ELX RAAL), S2EXv2 surrounds, HTM200SEx4 heights, Rythmik E15HPx2
* VPI Classic 1+ (VTA & Fatboy Gimbal), PE Eagle/RR, VAS NOVA, Soundsmith Paua, Manley Chinook, Bob's Devices SUT, SugarCube 1 mini
* Oppo 203 & 103D, EverSolo DMP-A6
* miniDSP Flex, Audiosensibility & Blue Jeans cables, Symposium & Isoacoustics, GIK
* For RDJ: Anthem MRX720, Sierra LX, Luna Duo v2 center, CXNv2, TBD