Making tails of 1/8-notes invisible?

[Joyce Wilson]

Is there a way to make the tails of un-beamed 1/8-notes invisible in Lilypond?  
A colleague and I are working on a transcription project which includes some 
plainsong pieces notated in both medieval-style notation and in more 
modern-looking notation, which has the unusual characteristic of using notes 
that resemble beamed 1/2-notes to represent ligatures.  You can get an idea of 
what we want the output to look like here:

http://www.box.net/shared/dttk0z54eq

My colleague has discovered how to get Lilypond to make note-heads white no 
matter what the note-length is, so our first approach has been to represent the 
beamed notes as 1/8-notes and the unbeamed ones as 1/4-notes, but we would 
prefer to come up with a way that would allow us to maintain rhythmic integrity 
in the Lilypond code (since beamed and unbeamed "1/2-notes" represent notes of 
the same length).  This would simplify the creation of accompanying MIDI files, 
among other benefits.  So if anyone knows of a way to make note-tails 
invisible, I'd be very grateful to learn about it.

Thanks!
Joyce Wilson

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