Perhaps there's a thinner aftermarket fan that would mate to the fan clutch--or perhaps one from another Mercedes model.
Notching an old aluminum fan would be something I'd try--some of my fans were missing chunks from various mishaps and ran for years without any problems.
I also used an old rear dome-light switch to manually control the auxillary fan--the switch just fits in the "Fasten Seat Belt" slot in the center console
Tim Kraakevik
kraakevik@voyager.net