Roy Harper?
 

Folk music, that's a bit progressive. I guess some might recognize him from the vocals on "Have a cigar", but anyways, his best known release, Stormcock would be a good starting point and would best represent his music. Has an excellent voice, some great lyrics and his guitar work is really versatile. His voice and expression keeps changing a bit, depending on the mood of the song.
Although It's only four tracks, most of it is too long to be uploaded on youtube. I'll upload a compilation soon...when my net stops acting weird again.
I think one of the songs could be uploaded, as it's below 10 minutes.

YouTube - Roy Harper - One Man Rock 'n'n Roll Band

The rest of the album is more or less in similar vein, only better. Just look up on the related videos.

MySpace

Hats Off

lol, thats wat i said.