I'm currently in the process of installing a 130A alternator into my W126 with M117.968 (5.6 ECE) engine.
It came from a Saab 9-5, and the overall dimensions are almost the same as the stock 80A unit. It was cheap at £20 ($30US) so I thought i'd have a play.
With a couple small modifications, I have the pulley installed, but just need to shave the mounting bosses back by about 1.5mm and install a 1.5mm spacer at the front of the mounts to keep the pullies aligned.
Will let everyone know if it actually works!

Ben