One of my writer resources came up with these sites for info on Medieval Scotland. They look great.
This one is great because it features a collection of articles for costumers, and it includes information about hair and hats: http://www.virtue.to/articles/
Wikipedia, of course, has a nice page: http://en.wikipedia.org/wiki/1200-1300_in_fashion
Medieval Scotland is worth poking around on for a whole host of info: http://medievalscotland.org/
The Costumer’s Manifesto has a ton of links that might prove useful: http://www.costumes.org/History/100pages/medievalinks.htm
Clothing of the Medieval Scottish Highlands is good too: http://www.marariley.net/celtic/SentToKass/Scotland.htm