Why would any 68k Mac need a flickerfixer? With a simple adaptor, those machines can put out some of the most well-behaved VGA in the land.
Speaking of other platforms, the X68000 could really use an sd/ff. Even in 31khz mode no LCD found to date works decently or at all with one thanks to it's high resolution and odd refresh rate. Unfortunately, tracking down the schematics to something like that is probably going to be much harder than finding the LC III schematics.