Mark Deutsch puts about 30 sympathetic strings on a 5-string upright bass and calls it a Bazantar.
Direct yt link
Higher quality video at Vimeo
It’s a YouTube vid for which embedding is disabled, so click here.
Specifically this Inconstant Sol post, atwhere you may download a live set from 1982 of an Arthur Blythe band with Bob Stewart on Tuba and Kelvyn Bell on guitar.