Looking for information on kilts? Here is a start.
http://www.xmarksthescot.com/forum/forum.php (http://www.xmarksthescot.com/forum/forum.php)
http://historum.com/european-history/96374-how-common-were-kilts-17th-c-scotland.html (http://historum.com/european-history/96374-how-common-were-kilts-17th-c-scotland.html)
Interesting discussion links, Westie, thanks!
I think many just tend to say "kilt" when they mean "belted plaid" (although not equivalent).
Modern pipeband pipers wear a kilt and a plaid as separates, I suppose to simulate a belted plaid.