Plus I'm looking for caps where I can decide what's printed on.
I think best might be to print decals on decal paper to put on the
front of the keys. That way, the custom legends will not interfere with key feel.
There are different sticky decal papers for ink-jet and laser printers - but the very best result (and most difficult to apply...) may be accomplished with waterslide decal paper you can get from a hobby store that sells supplies for building plastic model kits.
There are two-piece "
relegendable" keys, with a clear top under which you can stick a paper label.
However, these are often available only in a single row-profile and often completely flat on top - making them somewhat awkward to type on.
Best might be
Signature Plastics' DCS relegendable that are actually dished and with legend also in front.
These should be fairly close in height to the function key row of Varmilo ...
Relegendable caps are otherwise most often used on Point-Of-Sale systems - i.e. cash registers, and I think most such keys that people actually have were taken off cash register keyboards they got on the second-hand market.
