As far as I know there is no available font type that includes colourization, yet my idea for the eutofont font format specification does include chromatic capability, though, as far as I know at the time of writing this post, a rendering system to produce a display from a font made using eutofont font format has not been implemented.
Just in case any reader reading this thread is interested in reading about the eutofont font format, there is a thread in this forum about it, with some links.
http://forum.high-logic.com:9080/t/the-eutofont-font-format/683/1
In relation to wanting to produce results now with what is available now, one possibility is to consider making several fonts, one for each colour, and then using them in layers using a desktop publishing program.
The following thread from 2005 might be of interest.
http://forum.high-logic.com:9080/t/galileo-lettering-font/834/1
It is about my Galileo Lettering font.
I gradually developed a collection of fonts. Eventually there was a set of five fonts available, so that I could produce effects such as the following.
http://www.users.globalnet.co.uk/~ngo/mosaic3.PDF
Please note that no colour information travels with the font. Each of the fonts is black and white. The colours choices were made within the desktop publishing program, one colour for each layer.
The fonts are all available for free download from the web.
Producing a document with letters that display as if they were colourized letters will, as far as I know, involve making a collection of fonts and using them with layers.
I hope that this helps.
William Overington
18 October 2010