I suspect you will have to do a custom order (Etsy, Skinth Solutions, ...) or make something yourself. The Handyman is a great knife, but not a big seller, so it's generally relegated to using the same cases as its bigger brother, SwissChamp.
We had a thread a while ago where a member showed how he made a slip sheath for a SAK using shrink tubing, another guy made a belt sheath from bicycle tyre inner tubes. I guess those can be adjusted pretty much arbitrarily and would be pretty hard to beat for a tight and slim fit.