Fretless U-bass needed

I am trying to track down a fretless solid body U-bass,(sub?) but don't seem to be able to find one at the moment, can anyone else find one for sale.
I have a fretted mahogany top u-bass and really like the sound and the portability but have found that it is real easy to not quite get enough pressure on the string to stop the fret fart and so my poor little middle finger joints are really getting painful.
Have had to leave it at home and go back to the Hohner fretless again but swinging a plank of wood round my neck all night it just getting too much for this old gal.
Any ideas?
Bassdiva

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