How do I change the color depth of a monitor in Lion/10.7? How do I change the color depth of a monitor in Lion/10.7? I vague remember it being an option in the display prefs or the display menu bar in an older OSX version, but it seems gone in 10.7?
You're right in that Apple removed the option to switch between "Millions" and "Thousands" of colors from the Displays preference pane in OS X after Leopard (10.5). 

I've not tried them, but something like Display Maestro or SwitchResX both appear to have the ability to change color depth and might help.