I remember that happening to me with previous versions of VL, with a 1440x900 monitor. That resolution is now there.
It might take its time, but the trend is for more and more resolution settings to be added to the installer.
There is a message there about editing xorg.conf for additional settings, such as the refresh rate. Maybe there should also be a message in that screen that told users to edit xorg.conf if their resolution isn't available to be picked.