This poster from the Avett Brothers Koka Booth Show on 7/26/08 in Cary, NC, is up for bid on eBay.
According to the seller, the poster is signed by the entire band: Scott Avett, Seth Avett, Bob Crawford, and Joe Kwon.
I recently encountered one of the Avett Brothers--either Scott or Seth--in downtown Asheville. I was standing on a corner when a women next to me went wild at the sight of a man standing across the street. She was screaming like she'd just seen Bruce Springsteen. It turned out to be one of the Avett Brothers, who came across the street and gave the girl a hug and a warm hello. I asked her who it was when he walked away, and she said that it was one of the Avett Brothers (either Scott or Seth, I can't recall which). Since they play Asheville regularly, I knew of the band, but I couldn't pick out any of the individual members in a crowd (obviously).
The Avett Brothers will be playing in Asheville this New Years Eve.