Has a general aviation twin-engine turboprop with counter rotating propellors ever been built? In my experience with general aviation twin-engine turboprops I've never heard of one with counter rotating propellors. I've never seen any data about an engine manufacturer building left-rotating turboprop engines.

I'm also curious if any counter rotating twin-engine turboprop aircraft exist outside general aviation as well.
The only aircraft with turboprop counter rotating propellers that I can think of is the Piaggio P 180 Avanti, whose design is unusual in so many ways. 

Check out http://www.mpa.piaggioaerospace.it/, which gives the specifications of a Maritime Patrol Aircraft(MPA) based on the P 180.