Looks like a Jet Ski or Snowmobile on wheels. Street legal, hmmm??? http://www.youtube.com/watch?v=L6bmPt7CXQo
That's a BMW Street Quad. It's not street legal in the United States but is in parts of Europe and the UK.
What about these? http://www.youtube.com/watch?v=UBY-vRwsnAk the Bomardier Spyder or http://www.youtube.com/watch?v=38TFetQAe2o The T-Rex
I saw one of those in person in Dallas a few years ago. It was pretty impressive! He had plates on it and everything! Maybe he was a mini truck owner wanna-be! He probably moved to OK, though.
Ah...at least in the US, three wheels or less = mototcycle. So it's a whole 'nother ballgame. My favorite trike is THIS ONE