This is a pretty popular hack, but cool nonetheless. Rather than reconstructing the entire optical train, it's possible to mate the scanner element to the back of a large-format camera. Check out <a href="http://golembewski.awardspace.com/index.html" rel="nofollow">http://golembewski.awardspace.com/index.html</a> as an example.
Cool shot of him working on Blackberry source code: <a href="http://www.sentex.net/~mwandel/tech/scanner_pix.html" rel="nofollow">http://www.sentex.net/~mwandel/tech/scanner_pix.html</a>