Yep.. regular visits to the Ongoing Mystery Aircraft Thread
http://www.sim-outhouse.com/sohforums/showthread.php?t=17
will show numerous ones that take days to drag from extensive libraries and searches and a few that have caused a white flag of surrender to be flown.
The difference with the ones "up here" is that they are mostly aircraft from the average lifetimes of current SOH members so the odds are pretty good someone has seen them IRL.
BTW Ken, if Cessna had resurrected the 310R engineering and performance but been able to go back to the 310F appearance, it really would have been a winner in my book. The 'zoomie' 310's remind me too much of the 60's chrome/fin wonders from Detroit but the 310D/f was classic.
Rob