I am also interested in the '01, 3.0 trailer hitch.
I googled the dalan string and found the usual players, but several pages back found this quote inside the merceded benz club site

"I work for Curt Manufacturing the nations leading manufacturer of towing products. Our current design list includes many new Mercedes models. Please contact me if you are interested in helping us finalize a design for a NEW Mercedes. For existing Mercedes hitches look us up at www.curtmfg.com or contact our affiliate DALAN HITCH at 1-800-325-2613"

I do not know if it will helpful, but I plan to contact them on Mondy to see...