...they actually had menstrual panties! They were made by a company called "Harlon." They weren't made to absorb like Lunapanties but were meant to be a barrier to prevent leaks. They had a moisture-proof panel built into the crotch. I was quite surprised to see them to say the least. They were quite cheap (about $4). I didn't buy any but I thought I'd share my find with everyone else. Here's a website for the product in case anyone is interested in checking them out.
http://www.harlon.com/hcd/en/main.cfm?page=menstruationOf course if you live in southern Ontario, you might want to check out the Len's Mill Store in Kitchener!