Hi Holger and Dennis,
I'm already using PCBs as front panels for prototyping purposes:
It's very cheap and convenient. I was rather looking for something not so "prototyping" and "internal" use.
Holger, it seems the minimum of one solder pad is needed for gerber drilling information.
Kicad is unable to generate correct gerber files if there's not at least one.
Shaeffer AG is well known but expensive. Another potential manufacturer is beta-layout.
I've never tried any of them.
Best regards,
