Well ThomasPin had one for the W126s, at least at one point in time. He started charging for it, like $30/yr. Another guy emailed me before and said he was starting his own DIY mercedes page too, but I don't see much more than a homepage at the URL he gave me. As far as from me, it isn't very probable as I'll probably drive either a W123, W124, or a non-Mercedes diesel.
Thanks Deluxe Jb.