A small error in my last message.
While IPA does use macros and breves, it's not to mark vowel length;
that's what the American vowel system uses them for. IPA uses macrons
for high level tones while the breve is used for ``the weaker element
of a diphthong''.
But it's irrelevant what meaning is attached to a given symbol -- the
need is for the symbol itself.
By the way, another place to plunder symbols is from math fonts ;-)
They have a lot of stuff that ends up being useful outside of
equations -- I've used math symbols as repeat characters to form a
border or other decorative line, wide tildes for something or other
(wide tildes in TeX), section dividers, and so on. I find it handy to
print up char charts of fonts just to have a reference on hand should
I need to find something `interesting'.