Leatherbee (iirc) made one; they had it at Publican for awhile. Here's the problem: Malort is a Bask, which is its own whole kind of digestif. If you make a Malort-like Bask on purpose, as opposed to finding it in a puddle in the basement and bottling it like Jeppson's did, what you come up with will probably be fine. I remember not hating the Leatherbee stuff (but it was incredibly high ABV and we all got pretty messed up on it).