If you go by their product releases and nomenclatures, the Cobra S120R would be synonymous the Cobra iRadar 100 since it has strict support for only iOS devices. That's probably why they changed the product number from S200R to S120R and dropped Android support after the product announcement. Maybe next year they'll release an iOS and Android version of the S-series.
Also the Atom is quite small, so maybe I could live with it tucked front of the mirror.
The only other option for Bluetooth that is semi hidden is the Escort Smart (that I've found). I already checked with them, theirs doesn't work under the hood, it must be installed on the windshield. It's $450ish so it's not super expensive, but it's bigger so harder to hide. But Escort get's really good ratings from both the testers and the users.
Though quite honestly, I am surprised nobody has made a radar detector that is actually built into the actual rearview mirror. I've seen all sorts of things embedded in there; like compasses, temperature gauges, garage door openers, concierge systems, cameras, gps navigation, and rearview monitors. Just about anything one can imagine except an actual radar/laser detector.
Donaldta: same thing, with Parrot, you won't need any display like the mirror integration. The app makes all that unnecessary. I should make a video of all that working. In fact, Escort Live makes my controls/display module unnecessary as well. I can control 100% of day to day activities from the app. The only time I'd need to use the controls/display is to change some deep settings (turning on/off specific Ka bands (making it MORE sensitive to the bands used in your area)). Thing is, I did that once & I've not needed to do that again. I also just remembered that I could change those settings when I connect my laptop to the detector to update firmware/database, still making it where I don't need the controls.
One thing I thought of that WOULD require the controls & in the car is being stopped in a state that doesn't allow detectors (LA/DC/VA). You'd need to power it off if you were to be stopped.
But, I would definitely appreciate seeing a video of it all working on the Asteroid Smart.