Either Levente or Christoph recommended something named Unifont.
I just did a search http://unifoundry.com/unifont/%C2%A0 and it claims to cover all glyphs in True Type.
I will be messing around with this next.
Hi Timothy,
I spent several (fruitless) days last year trying to get cuneiform fonts to render properly in Squeak (see https://www.hethport.uni-wuerzburg.de/cuneifont/ for examples of the fonts). There does seem to be an issue with rendering glyphs above a certain code point from what I recall. I am definitely interested in your work and what you end up finding out.
If you can find a character range, we can try to get them to appear in the browser. My Seaside is coded for UTF-8 .