Sure, manual regulator assemblies exist, if you can find one for a w126chassis somewhere. (In Europe the w126 could be had with manual windows, orfront power windows only.)
Crank regulators for the 126 would be _much_ harder to come by in the US than the power ones. And you'd have to find a crank, drill a hole in your door side panel, and color-match the insert. And all this would not increase your resale value at all. -- Jim