Not mine but I thought this was interesting… 
http://cgi.ebay.com/UNICYCLE-ONE-WHEELER-VERY-UNIQUE-VERY-RARE_W0QQitemZ320455606550QQihZ011QQcategoryZ2904QQcmdZViewItemQQ_trksidZp3286.m7QQ_trkparmsZalgo%3DLVI%26itu%3DUCI%26otn%3D3%26ps%3D6#ht_1332wt_950
That baffles mah mind.
Seriously 
That dude seems to be making some sales, too.
Stuff I don’t believe on that guy’s auction page:
“VERY UNIQUE” - Unique doesn’t come in degrees. It either is unique or it isn’t.
“ONLY 7 EVER MADE IN THE EARLY 70’S” - That wheel is definitely not from the early 70s. Though it may be a replacement wheel, I’ve never seen one like it, let alone customized to work with a unicycle. Remember, it has to attach to a uni hub. My guess is early 80s for that cycle.
“I BOUGHT THIS FOR $250 DOLLARS” - You’re not that stupid.
“I have been working with E-Bay selling and buying items since the early 1990’s” - Though it’s possible he’s been with eBay since their obscure origins, I kind of doubt it. That was 1995 (according to eBay’s own About Us page).
The cycle might be fun to ride though… AFTER you swap out that narrow seat! Try that seat on a road uni with handlebars maybe, on a recumbent like that, you’ll have all your weight on the seat.
Unique?
Yeah, I,ve seen it in these forums before. Also in MountainBikeAction magazine a couple of years ago. It’s a “Wheely Bike” made by some guy at Haro and it’s closer to the 80’s (good eye on the wheel John) I wish I could find the issue to relay the whole story
That is 1 weird looking unicycle… i like it.
Oops, I lied about the wheel. Still mid 80s or so, but it’s a chain drive, so it doesn’t need a unicycle hub. It still may have required customization if it started as a coaster brake hub though…