It appears I am joining the club on wiring harness woes too. I just had my head gasket done at my local indy(migraine #1) and was hoping to get away with not having to deal with the wiring harness issue. Of course, when the engine is all sealed up, the engine misfires and runs very rough. They discover shorting in the harness (of course) and are now trying to put some liquid insulation on the shorting pieces.

I called up MB and they say that there is no official policy and any goodwill service is left up to the dealership which will take into account the current state of the car, mileage, etc. (knew that)

I called up the local dealership who of course denied any knowledge of problems with the wiring harness. They did ask me to fax over all the info I had. I don't know what they will do about it but I did find the following safety recalls for my car which I sent to their attention:

95-0223 Safety Recall - Wiring Harness Chafing/Shorting
95V031000 Wire Harness Protecter Installation

I will keep you posted!