Zeta JM25
Once upon a time, electric violin company Zeta was based in San Francisco, and very briefly had an acoustic/electric mandolin in its line (below)—which from all appearances was just a rebranded Asian-built F-style.
     As of 2016, however, Zeta belongs to former Flatiron mandolin builder Steve Carlson and is located in Montana. After finishing his first run of 44 violins, Steve branched out into his old territory and designed the JM25, an acoustic/electric 5-string mandolin that's fully MIDI compatible.