- a selection of portraits can be found on the National Portrait Gallery UK web site http://www.npg.org.uk/live/search/portList.asp?search=ap&subj=90%3BHats+and+head-attire&page=2
- Dawn provides a selection of flat caps, she suggests that they are sewn but I think some of the hats pictured, especially those with the turned up brims, definately could and probably would, have been made from felt. The brims would stay up better. http://www.reddawn.net/costume/hats.htm
- although this hat looks like it was sewn, possibly out of leather? http://www.npg.org.uk/live/search/portrait.asp?search=ap&subj=90%3BHats+and+head%2Dattire&rNo=13
- wikepedia also has some interesting info and pictures - here is some general fashion information with sections on head gear for women and men http://en.wikipedia.org/wiki/1500-1550_in_fashion#Hairstyles_and_headgear and here is a close up portrait showing a barett (looks like a felted beret to me) http://en.wikipedia.org/wiki/File:Hans_Baldung_021.jpg
let me know if you find anything else!