There is an old miner in Butte, Montana named Onder Mayes who came there from the hills of Tennessee. He is the only fellow I'ever seen seriously flatpick the 5-string. He also used a highly individual G tuning. I believe it was;

gGDBD but I don't remember exactly, offhand. He sang the old mountain music in a high thin tenor, THE HILLS OF ROANE COUNTY and such, and would sit there in Harringtons'Bar,drinking beer with ice and singing for the drunks, young and old. He also was known to play the fiddle on occassion, but that's another story.

Mark Ross