It looks like the result of some deranged cross-breeding experiment involving a guitar, a banjo, a violin and a hubcap.
He’s using a bottleneck on his left hand and banjo picks on his right. It makes an impressive array of sounds but I’ve never seen one of these in the UK.
So what is it?
Romulus Crowe 
Dear R,I followed the link to republicguitars.com at the end of the video and found lots of similar looking instruments for sale.The violin-y parts seem to produce similar effects to the violin itself. To my delicate ears, at higher frequencies, they both sound like a cat being bonked by an elephant. Using vindaloo sauce for lubrication.Sensitivity to high frequencies probably explains my aversion to children as well.Keep on headbanging,h
Sorry about the delay. This thing is supposed to Email me if there's a comment in moderation.It doesn't work.
These things 'appen as we say oop north. š
It's a resonator guitar or resophonic guitar.http://en.wikipedia.org/wiki/Resonator_guitar
It sounds amazing. I must get one.