Decapitated flats

I was looking for those little accidentals that look like a flat and a double-flat both
with their tops chopped off, like the ones that the Huygens-Fokker website uses for
31-tET. Does anyone know of a font containing them? Ted Mook's Micro 2 does not
appear to have them, and MidiDesign's Sonora <http://tinyurl.com/2gn64> has a
only a bunch of otherworldly squiggly things. (Entertaining, but does anyone know
how they were intended to be used?)

Thanks,
Jacob