"2000 + variants"
A bit of an exaggeration I think Malcolm, performances maybe - hardly variants - Bronson gives around 200 - hardly likely to have increased that much in the intervening years.
There is a Library of Congress LP made up entirely of different versions of Barbara Allen - 30-odd, I sem to remember.
"Is Barbara Allen a traditional song?"
It i probably fair to describe it a THE traditional song.
Jim Carroll