Making a custom 16:9 resolution?

[ThunderSock]

So my mac is connected to a 1366x768 16:9 TV, and I want to lower the resolution to something like 960x640. Apparently OS9 supports 16:9 but it doesn't offer any presets at that aspect ratio (except native resolution). The reason I'm trying to do this is the games I want to run mostly sit in a 640x480 or less window (which is tiny at 768p), and the TV stretches any input into widescreen (stretched images look really nasty ).

Can I force OS9 to display 960x540?

edit: fixed numbers

[macStuff]

i ran 1680 x 1050 on my samsung with a geforce 440mx - it just worked
on windows 98 i had to hack the drivers with a text file

[GaryN]

You can try Switchres2:  http://www.madrau.com/SRXv3/html/SR2/DL.html

Be very careful! It's possible to set a resolution that your monitor cannot display at all, and then you'll have a hell of a time getting it back when you can't see anything!