Doctor M said:
http://avisynth.org/mediawiki/External_filters#Transitions
DissolveAGG might be best since it provides a wipe with a soft edge.
Set one side as the default color balance, and the other clip with the altered colored balance and try to match the wipe speed.
Fiddly to pull off, but do-able.
Thanks, Doctor M!
Sounds very hard to pull off, will check it out.