I too had been conducting a very long search for a case for the Hadean acoustic zebrawood uke bass I got from Rondo.
I bought a few and none fit, and had to return them.
This is DESPITE taking accurate measurements and reading all the specs where each case was sold, and dimensions are not always quoted to match the physical reality of the case.
Finally, I found THIS case below:
http://www.smallguitars.com/catalog/302-Hard_cases_GQC_1-4_size_acoustic_guitar_hard_case
Which fits the Hadean and is just barely wide enough for the tuners.
What MOST folks do NOT realize is that you need about a 5.5" space INSIDE the case at the headstock otherwise the foam case will NOT clear the tuner buttons and will press on them, which over time WILL cause several different problems, which include eventually the tuner buttons will cut through the case foam, this defeating the case protection, as well as damaging the tuners, and/or causing them to either bent or separate from the headstock due to pressure against the tuner assembly from the sides at the tuner buttons.
I've found many times folks just dont read details in threads and gloss over small details like this, but this is al VERY important.
If I had to do over, I would have likely just gotten the Kala rectangular hard-case for their U-Bass, but I did not want to spend that much ($99), but instead spent LOTS of time trying to figure out a cheaper alternative.
"Penny-wise and pound-foolish" is what I did - learn from my mistake.
FYI- I AM NO LONGER looking for a case now, this was all done over a year ago.