Why pay all that much money for a Nikon product, or go to the trouble of making one yourself when you can buy a very good alternative one for £9.97 inc P/P & ins. I've got one, they're very good and work a treat!
Here's the web link.
http://cgi.ebay.co.uk/Remote-Cord-to...QQcmdZViewItem
You might have to wait up to 10 days for delivery, but it's worth the wait.
nirofo.