In the MMD Archives I found some discussion about the ability to
convert the MIDI velocities to expression notation for piano rolls.
I did not follow all discussions afterwards so I am not sure that
I still can contribute something usable this moment.  But you never
know....

A few months ago I introduced the program "Midiboek" for Windows.
It is a template printing program.  I did write the program myself and
I am rather well introduced in the secrets of MIDI.  When I rewrote
Midiboek for Windows (originally it was a DOS program), I conceptually
prepared the program for other purposes than template printing only.
One of the users of Midiboek now feeds his automatic punching machine
with the print script file of Midiboek.

I made some small modifications to that file, enough to be able to
control the stepper motors in the punch.  (Potential) users of
automatic punches are encouraged to inspect this file and to see if
they can do something with it.

Okay, back to the expression holes now: if anyone still wishes to use
the velocities in MIDI files for this purpose, I suggest to him/her to
download Midiboek (it is free) and see if the basic features meet most
of the requests for printing templates for piano rolls.  If so, contact
me and I will see if I can build in the expression feature.

I realise that Midiboek has an important disadvantage: it can not print
continuously on pin feed paper.  But I will try to find out how much
work it is to realise that if there is enough interest for.

For your information: within a reasonable period of time, Midiboek 3.0
will be available that supports English besides Dutch.

Best wishes for this first year of the 21st century, and
best regards from

Piet Paardekam
Zutphen, Netherlands