Joppu, that looks very cool! It will certainly help with race-induced dreams

Jolouis once explained to me:
The main time is simply a set of images, named 0.png - 10.png that are displayed in the co-ordinates defined by the theme file according to whatever time that digit is supposed to show. So for example, if the time is 12:41, the digit 1.png is rendered at the first position, 2.png at the second, 4.png at the third, 1.png again at the fourth.
If a digit is supposed to be blank (i.e. 2:40, the first digit is blank), then 10.png is rendered in that digit's position.

I don't think that different glyphs are possible.