Fonts aren't platform independent. An image of a font is.
Just a little experiment with Graphics2D in Java. JavaAgent running on WebQuerySave generates an image (and embeds it in the document) from header-text, selected font/-size. Also adds a shadow if desirable.
Width is currently hard-coded (400px), so the biggest fonts, with font-size set to 96 won't fit.
I use a Java WQO-agent that sets a multivalue field containing all font names in GraphicsEnvironment.getLocalGraphicsEnvironment().getAllFonts(). This way, you should get the fonts available on your machine/server.
Header-images are saved as png in the systems tempfolder.