While not exactly what you are proposing, ff you want/need to use characters as icons, there is a pretty neat hack called Font Awesome (http://fortawesome.github.com/Font-Awesome/). It's used to replace the twitter bootstrap icons with font files; seems to work pretty well so far (with no need to re-color individual icons... you can style the font/icons with css).

Things like <div class="icon-flag" style="color:red; font-size:36px"> will create a 36point red flag character for you.