There was a great collaborative song writing project on Hadrian's Wall a few years ago involving singers/musicians Boo Hewerdine, Jez Lowe, Julie Matthews, Rory McLeod and Ruth Notman and poets Kate Fox and Elvis McGonagall. They wrote some great songs, but achieved it by holing up in a house together for a week. Fellside Records produced a CD :
http://www.fellside.com/shop/Details.asp?ProductID=694