Custom articulations?

[Hilary Snaden]

This defines a new articulation which displays a very small trill symbol:

newTrill =
#(let ((m (make-music 'ArticulationEvent 'articulation-type "trill")))
     (ly:music-set-property! m 'tweaks
       (acons 'font-size -3 (ly:music-property m 'tweaks)))
     (ly:music-set-property! m 'tweaks
       (acons 'padding 0.50 (ly:music-property m 'tweaks)))
     m)

but is there a way of defining a new articulation which displays a trill 
symbol in parentheses, or "tr" in plain type, to show editorial trills? 
This would be *very* useful!

--
Hilary Snaden