I'm not finding the link that I'd seen here right off the top of my head, but take a look at these:
link link
They both run through the whole procedure fairly well.
I can't think of any spectacularly difficult additions on MB's part.
I found it easiest to jack the car up, putting it on jack stands, and to remove all the wheels before doing the bleed, but I suppose if you were exceptionally determined, you could probably even accomplish it without removing wheels.
Edit:
I found a link regarding bleeding brakes on w126 cars, not quite a SL, but related...
here