A latin proverb on the arm of a proud Scot, one of the few peoples who stopped the Roman Empire, is quite surprising, although I certainly find the sentiment appropriate. (From my readings, only the frisians and suebi so frightened off the romans.) It's like "sisu" among the finns. In the face of such indomitable peoples, the imperial commanders declared, "I came, I saw, I drew a line on the map and ran home like a whipped puppy!"
Otherwise, if you're looking to backwards-engineer a folk song, why not go to the extreme end and pull some snippets or ideas? Check out Alan Parsons Project stuff maybe. Just guessing, but themes from stuff like this might be useful: Time, Ammonia Avenue, Don't Hold Back, Children of the Moon, Old and Wise, Closer to Heaven, Can't Look Down, One More River, Mr. Time, Days Are Numbers, Same Old Sun... not necessarily my favorite Parsons Project songs, but ones that might have usable folk stuff in them. Play the whole catalog of his Project work and I'll bet you get some good ideas somewhere.
If you can do a folk version of "Return to Tunguska" with such weight, I'll be suitably impressed and demand a copy :)
Oh, and right now I'm listening to "L'arc en Ciel" from his "A Valid Path" album, just for the record:http://www.youtube.com/watch?v=3uGLCAJrm1g
In case you didn't realize it, I DO have a sense of humor. How about you?
"I will not fear. Fear is the mind-killer... I will face my fear. I will let it pass over and through me, and when it has gone, only I will remain." --The Bene Gesserit
"Time is a spiral. Space is a curve. I know you get dizzy, but try not to lose your nerve." -- Neil Peart
"I'm not in the ship. I am the ship." -- River Tam
"The truth is simple. It's the lies that get complicated." -- me
"No matter where you go, there you are." --Buckaroo Banzai