Many articles say how rare the glass harmonica is, and how hard it is to find a proficient player, so that many orchestras use a flute instead. Well. I believe they have forgotten about the theremin.
Here's some Pink Floyd. Yes, Pink Floyd on the opera blog.
and to keep it classical, here's Ave Maria:
So if you put this dude in a tux and taught him Lucia, I bet he could step in for a broken glass harmonica, don't you think?
Ahhh that Pink Floyd is so calming.... Maybe I've found the antidote to opera keeping me awake.