Eru, I've finally got a chance to sit down and do a search for folk music! It's hard to avoid the stuff that was written in the sixties, based on folk music...not that that's bad stuff, it's just not what I'm looking for...but I'll see what I can do.
My favorite aspect of folk music might be the mountain dulcimer. It was especially used in Appalachia (the southern Appalachian mountains- I live on the other end, not far from the northern mountains), and is not dissimilar to the hammered dulcimer (my favorite instrument!). Another instrument might be pennywhistle or tin whistle.
A lot of songs were penned during various wars- you've no doubt heard Yankee Doodle, made up by the British to make fun of the Americans (who promptly adopted it as their own).
Here's some Mountain Dulcimer (it is, unfortunately, electric, but it still sounds cool!):
http://www.jcrmusic.com/audio/streets_of_laredo.mp3
I'm afraid I haven't been able to find much more than that...I keep coming up with the modern stuff! If I do find more, however, I will post it for you to see.

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I am a Shieldmaiden for Christ!
I was Nienor before Nienor was cool. *nods coolly*
Kudos to Kitoky for the fabulous signature set, and art credit to
engelszorn.
Who wants to join me in bringing back the lady?