Today I found myself wanting to look through all of the fonts I had that implemented a specific Chinese character so that I could choose the most attractive. I tried
GNOME Specimen, but that wants to list all fonts, rather than just the ones that implement the codepoints you're interested, so many entries are in fact showing the fallback font.
It turned out that it was not very complicated to implement a
quick program in PyGTK that shows what fonts implement a specific set of codepoints.

Run it using
./compare_fonts.py <string>.
This sort of filtering could probably be incorporated into GNOME Specimen. Personally, I'm thinking of adding it as another tab to gucharmap.
P.S. PyGTK guys... the Python Pango docs appear to be missing symbols that exist in the modules. I had to find some of the API I needed from the C docs.