How do I change my resolution on my Mac to a custom size?

Solution 1:

I think I may have solved this problem, after a lot of experimentation, but I only have one system to test it on. Watch Custom Resolutions in Mac OSX, no software necessary!. The video references this website, #MacOSX : Display EDID [UPDATED]

Basically, I'm editing the plist file that sets which resolutions are allowed. No software or money required.

/System/Library/Displays/Overrides/ contains the .plist files with the resolution options OSX uses for displays. I'm running ioreg -lw0 | grep IODisplayPrefsKey to figure out which one is the primary display, and then adding an entry for the custom resolution. It's basically what SwitchResX does, but without all of the software.

This is on OSX 10.6.8, though, so I don't know if it's applicable to Lion.