While the intended market for these (and the tornister tubas) seems to be people who "travel" (for one reason or another?), I wonder if there isn't a market for these sorts of things in the population of aging community band low brass players who have difficulty with "normally sized" instruments. I know several people who have changed instruments to smaller ones because they no longer feel able to carry/transport the instruments they've played for most of their lives.
Of course, this depends very strongly on the weight of the "downscaled" versions. And the only tornister tuba I've heard close up (rehearsing in a fairly small tuba/euphonium group a few years ago) was not something I'd want to use in a community band. Still it would seem to be a possibility, at least if you weren't the sole tuba in the band.
Gary Merrill
Wessex EEb Bass tuba (DW 3XL or 2XL)
Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
Amati Oval Euph (DE 104, Euph J, J6 euph)
1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
1947 Olds "Standard" trombone (Olds #3)