One of my work colleagues mentioned he'd bought a cheap plastic retractable-nib fountain pen on a visit to Japan and it reminded me of this thread. Naturally I went looking ...
Jinhao make a version, and there is THIS ONE the Majohn A1. What I found most interesting about the Majohn A1 is that they sell replacement nib units for it - LIKE THIS - which by definition means it's possible to disassemble the pen.
That's only a "short step" away from making a custom shell and fitting the nib unit & ink reservoir into it. Anyone up for the challenge? Even if the nib doesn't retract, it should be quite feasible to make one with a hooded nib.
