I've seen those basses around thanks for some background. Double Bass players want real db tone AND portability. I sell one or two EUBs a year ( eletcric upright bass) . My basses are an easy sell to a guitar bass player coming over to a 3/4 double bass, a little harder to a 3/4 db player used to a certain tone. My bass, very airline friendly, http://www.uglyhedgehog.com/t-393630-1.html I've also built a full size 3/4 db with a removable neck, as others have pioneered, to address the portability problem.

from the link http://www.newmelbournejazzband.com/

Ross Anderson with his own developed Anderson bass (photo courtesy: Ross Anderson)

Bass players might remember Ross Anderson's "undersized" double bass - He developed the instrument a dozen years ago. The Anderson-bass, easy to transport, but with the same deep sound of a full-sized double bass, is now a sought-after concept.