If you find a Mac to VGA adapter with DIP switches, you can often change the syncing mode. For me, the composite+separate sync setting works well for me on a IIci with a Monitor that doesn't like sync on green. I'm not exactly sure what this adapter does electrically. Maybe it's MAGIC! I've had success with several different adapters in this configuration.
As far as finding an LCD with 1280x960 native resolution, I guess I've never seen one myself, and a quick search turned up NOTHING. Maybe these are unusual or even non-existent. Very interesting.