I wanted a single pen case to carry my fountain pens: Waterman Carène, Parker Premier and Caran d'Ache Leman.
I found some interesting options, but had to import them. There was also another issue: I wanted a case that could also carry a spare cartridge.
What I did was, based on this Lamy design,
asking for a tailor-made one at a good shoe shop at my hometown - these people know how to work with leather. They even put a kind of shammy inside, to keep the integrity of lacquer and external paiting.
But what makes it really tailor-made, to my "specifications", was the little "pocket" to carry the cartridge:
Not that beautifully finished, but very functional.