What kind of adapter are you looking for? Power, Video, game cartrige, something else?
I don't see why you'd need an adaptor. The only difference between the two was the little tabs they put in the SNES to lock out SFC games from being played on it. All you had to do was break those little plastic tabs off and SFC games played just fine in an SNES as I know from experience. I'd figure it's the same the other way around where SNES games should play just fine in an SFC.
Drakul, Have you looked into the Slimline Super Nintendo that they released near the end of the console life? It looks more like a Super Famicom.