At the moment we have the Librem 14, which fits in a nice middle ground between the 13 footprint, but with a larger actual screen. Between that and the dramatically improved resources on it, it seems like it does fit a sweet spot.
However, I would be interested to know which of the features that are missing compared to the 15 (full-size keyboard with numpad, higher resolution screen, slightly larger screen, larger overall footprint) that would prevent people from ordering a Librem 14 instead.