Leah - I know old-timey players don't like to capo up much, but going up to the 5th fret (plus some railroad spikes in the neck) will change a G or G modal or minor tuning to a pretty good C and not sound too much like Chinese opera :)

I just found an old tape of Doc Watson doing Clarence Ashely's version of "Little Sadie" on banjo, and I liked the sound so much that I sat down and figured it out. Doc was playing in what sounds like Mountain Minor (gDGCD) capoed at the 5th fret, and his picking is really crisp and clean. I can't decide if its fingerpicked or frailed. At that fret, the chords are Cm and Bb, but a guitar can capo to the third and play Am and G for good backup.