foam cutter for rc planes?

Hi all,

Cool site. This is my first time here and need your help. Does
anyone have plans or know where I can get plans for a cnc cutter for
cutting flat depron/fanfold foams to make rc planes? What I am
looking for something very simple, cheap, able to cut through at
least 6mm foam, and uses a dremel or hot wire.
Something that is able to do this:
http://cnczone.com/forums/attachment.php?attachmentid=1193
Any help would be great. Thanks inadvance.

Sincerely,
Hong