The Asymmetrical Teardrop is a simple and robust design, and scales up nicely from Mandolin to Mandobass.
Usually the Mandolins are 14" scale, the Mandolas are 16". The Octave Mandolinds are on a 22" scale, Mandocellos are 24" and the Basses are 32 or 34" scale, to order.
Normally the Mandobasses are four string fretless, but can be ordered fretted, if desired.
This family of instruments are normally carved Spruce top, and Maple flat back and sides. Carved backs and other woods are low price options.
Good access to the 12th fret, and full play-ability all the way up. Extra rich bass response from the extension of the top over the bass side of the fingerboard.
Special woods, stringing and other custom features are no problem. use your imagination. Ten string Mandolin/mandolas are a good example, strung C-G-D-A-E, or ten string Mandocellos, string an octave lower are a useful instrument, or can be strung as Irish Citterns or Bazoukis as you desire.
I also make a full Mandocello on an 18"Jazz guitar body for a base price of $600.00.