With the dangers of a vacuum pump failure, I have been wondering about alternatives. I currently have an International 7.3 IDI V8 waiting on it's final home to be prepared, and got to looking at it- It has a belt driven, fully external vacuum pump. It almost looks as though you could make a bracket to mount that on an OM617, and never worry about catastrophic vacuum pump failure again. Just put a block off plate on the front of the timing cover, and your timing chain is safe.
Does this sound feasible?