Merriman .28cal Knife pistol Info Needed

I recently ran across a Merriman .28cal black powder knife pistol. This is in excellent condition and possibly unfired. It was in a wooden case, with balls, tool, primers, everything that came with it. I was curious what it could be worth and if there is a market for these?

http://www.hunt101.com/data/500/medium/DSC0000110.JPG
http://www.hunt101.com/data/500/medium/DSC0000311.JPG
http://www.hunt101.com/data/500/medium/DSC0000213.JPG
http://www.hunt101.com/data/500/medium/DSC000049.JPG