Here's another link that has some useful information about the kilt

http://www.apparelsearch.com/definit...definition.htm

The section The Kilt Today has:

As with any other form of dress, the kilt is subject to the vagaries of fashion. Since the 1980s, kilts have appeared in such materials as leather and denim. Single colours have also been used in place of tartan, particularly by people without Scottish links in countries such as Ireland or the United States. While these garments may be disliked by traditionalists, they provide evidence that the kilt still has a place in the modern fashion world.
So while your friend may be historically correct, he still needs to get up to date!

Brian