One of my 'when-I-get-around-to-it' projects is to drill a hole in a metal
Pentax body cap to mount a Polaroid MP4 Prontor shutter in.  I can then use
my MP4 lenses on a 35mm camera with bellows, or indeed in the field with
moderate convenience by using a helicoid extension tube.

Any of the MP4 lenses could be used, and I expect I'd get infinity focus
with the 135mm and possibly the 127mm with the helicoid, probably not with
the 105mm or less.  That would then be a 135mm portrait lens with a leaf
shutter that would sync. flash at any speed - stick an auxilliary finder in
the hotshoe and it wouldn't be impossibly inconvenient to use.

But the real reason I want to play about with this is for macro work.  Even
with MLU a focal plane shutter produces more movement than a leaf shutter,
and with the 35mm and 17mm lenses one is talking serious magnification.

May or may not be worthwhile, but I have (and use) the lenses already and
have the body cap and a spare shutter so what's to lose?  If it works out I
might make one of these up for my 6x6 system as well, though I doubt I'd get
infinity focus on it.

Peter