OSH '92 or '93: Help me identify this aircraft

I'm trying to figure out what type of aircraft I saw at Oshkosh '92..
or possibly '93. Here it is: High wing bird, parked in one of the
certified fly-in areas. The kicker: It had a motorcycle in it. Yep,
honest-to-goodness full-size bike. I *think* it was a BMW R90, but
it's been many years, I could be misremembering. Anyway, I would have
taken pictures, but by the time I got around to certified birds, I was
out of film (Remember film? You never had enough.). Anyway, I would
absolutely love to be able to bring a bike with me on various trips,
so I'm interested in figuring this puzzle out. From what I currently
know about airplanes, a high wing bird with a cargo door large enough
for a motorcycle might be a Partenavia, but oddly enough, I don't
actually remember it being a twin. But hey, 17 years is more than
enough to fog anyone's recollection..

slip