Castagnari's Lilly: This is a super small box that is great for some very specific applications. Obviously, it makes a great travel box. But it also has a very specific sound.
With 21 treble buttons and 8 bass/chords, it is a "full size" melodeon from the perspective of tonal range -- at least, for a two-row player! However, the Lilly is a single-voice box, which means that for each treble note, only one reed sounds.
Despite this limitation, the advantage is that it allows Castagnari to mount the reeds on a flat "pan" rather than in stand-up blocks. This heightens the responsiveness of the reeds and makes for a very loud box.
Theoretically, it should be possible to make a similar box, slightly larger, with 2 1/2 (or 3) rows and 12 bass/chords. Ahem ahem.