I just finished building this and thought I'd show it off. Twenty-one inch scale, Selmer shaped body, Pahoehoe strings, Shadow pick-up, Hip-Shot tuners, Sitca Spruce top, curly maple back, sides, and neck. http://i1278.photobucket.com/albums/...ps719b2b32.jpg
It's just a guess of course, but the larger body seems to make it two or three times as loud as a U-bass - enough acoustic volume to keep up with other acoustic string players.
Like my U-Bass, I can get something very close to an upright sound when plugged in.
There is a new string on the horizon, however, that looks promising: Aquila’s Red Series strings for the Shortbass in both 23.62 inch, and 26.37 inch scale lengths. If these strings pan out, and some good luthiers get on the stick, it means that Gypsy jazz bass players could now have what would amount to a Selmer/Maccaferri type guitar, strung up like a bass, sounding like an upright, and looking very much at home in a Gypsy jazz band.
(Scroll to the bottom) http://www.aquilacorde.com/index.php...d=1681&lang=en