I've been searching around and can't find a solution for this. The official NVIDIA Tegra 2 Linux SDK (L4T) doesn't include both XRandR or the VideoMode X11 extension for querying available video modes. My next thought was to parse the log file for video modes. Of course most of the time it's at /var/log/Xorg.0.log but I'd rather not always make that assumption. The XF86misc extension provides a way to get the log path but that extension is also not installed by default.
So I'm wondering if anyone knows of any other way to figure out what video modes are available and also what the current video mode of the display is.