Hit up 'ts' on here. He has/had a pair that I recall seeing pictures of. As for price, they come up so rarely often that it's hard to really give a good ballpark figure. They're really long and look like a PITA to run in the field. I think ts had his shortened somehow.
I've only ever seen one source with them, a GD show from 80/81 and it didn't sound like a good representation of what they could offer sound wise, compared to some of the other shotgun recordings I've heard. I'm not a big fan of shotties anyways, so take that for what it's worth.