Sarah: Don't know if this is what you're looking for but there is a book translated from Japanese about building a mini-gama (a mini-anagama) fired with charcoal I believe.
It's tabletop sized, and fires like the real thing.
The book is only $14. The information I have is:
The book is a translation of the work of Akira Yoshida and has been translated by Naoko Gomi P.O. Box 311, Princeton, MA 01541 snipped-for-privacy@yahoo.com
Hope that helps,