[BTW, I just tuned into this thread and it's looks awesome.]

You_Too said:

The GOUT has unfortunately been desaturated even after the scanning. In lots of scenes there are parts of the picture which actually has no color information left at all.

Without finding that frame (non-saturated) to examine it's problem in R-G-B before asking this, I'll just ask ...

Did you ever look into snicker's (excellent) concept of "repairing" clipped luminance (both high & low) by patching in non-clipped (or lesser clipped) same-areas from different R-G-B planes?
http://originaltrilogy.com/forum/topic.cfm/Harmys-THE-EMPIRE-STRIKES-BACK-Despecialized-Edition-HD-DVD9-AVCHD-and-SD-NTSC-DVD5-AVAILABLE-NOW-Read-1st-post/topic/12511/page/28/
Maybe useful in such instances?