I think this has some potential if it were realized as an application
with it's own window space and dedicated widgets rather than as a bash
script utilizing xterms and window-manager window-placement. It maps the
positions of the popup xterms to note-pitch and note-velocity.
I don't know though, it's probably been done already..
I sent it to LAU..
Here's the text describing it further, which probably is a good idea to
read quickly:
http://jwm-art.net/art/text/xwinmidiarptoy.txt
Here's the actual BASH script:
http://jwm-art.net/art/text/xwinmidiarptoy
james.