I had seen a bunch of notes inquiring about iron-on transfers here. You may
be interested in the Transfer Toners for laser printers from BlackLightning
black & white laser printers and offer 15 colors including process (CMYK).
The toner works with plain paper and creates a colorful permanent image.
You also may be interested in the Flash Magazine which has an article
each issue on this topic as well as general laser printing, dtp and
book-on-demand publishing topics.
Publisher & Editor
Disclaimer: I invented the Iron-on Transfer Toners, but hey,
they're still fun stuff! :)