He's supposedly got patent number 6,362,718, so presumably someone could build a replica based on the information in the patent document.
Here's a link: http://patft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&co1=AND&d=PTXT&s1=6,362,718&OS=6,362,718&RS=6,362,718