This is a little old, but the display timeout is in /etc/gconf/gconf.xml.defaults/system/osso/dsm/display/%gconf.xml (there's a whole world of fun in that /etc/gconf directory - I copied it all to my mmc to browse on my comp.)

Also, if you set one of the options to 0 (zero) the display never times out. I only set my dimming value to 0 and it still doesn't go off. It DOES, however, switch the screen off when the cover is put over the screen.

PS. I think you can get gconf editors for all sorts of platforms. Google and see!