Interesting, if true, although I suspect it’s challenging overcoming physics in creating a smaller subwoofer to move large amounts of air. 

Less power though, won't need to push as much air. Still be achievable with a circular design and will slot into places a lot easier, as the normal sub is pretty big. 

I could see this as potentially of use for a situation that I currently have:  2 Ones in a Stereo pair.  The current sub offering seems like overkill in that situation (primarily music in a home office).  But a smaller/less expensive mini-sub could work with music only application -- even non-critical listening.   

For movies/TV (not my situation), I could see wanting the larger sub.

Would be interested in a smaller sub to pair with my beam in the bedroom, can tuck this away neatly somewhere and won't be too overpowering. 

Also hoping some up-firing rears get announced..

This would be a great fit for the Beam, or a couple of Ones wouldn't it?

From a price and looks point of view, a smaller one would be a better fit, but from just a sound quality point, even the present one will elevate the sound from your One pair to HiFi or even audiophile class. Just make sure that true play tuning is done after it is placed somewhere between the two speakers, and bonded to the pair.