Finally figured what saving from lxrandr was doing. It's creating a desktop file in ~/.config/autostart that calls xrandr to set the resolution.
I had already figured out thru trial and error that for some reason, if I try to set the resolution with xrandr right after boot, it says no such mode. However, if I run xrandr (with no switches) then run it again to set resolution, it works. Not sure why, not required under other distro, but since it works... I modified the desktop file it'd created to insert "xrandr &&" at the beginning of the exec line, and wala, it works - at least at startup.
But, this only works at startup. If I play a game full screen, when I exit the game it reverts to 1024x768.
So short of modifying the desktop file for every app that can run full screen to add xrandr to set resolution as a workaround, I still don't know how to set default resolution.
I believe its something to do with xorg and changing the order of the modes so the desired default is listed first, but reading the slitaz wiki about it, it's hard to understand, and I dont even have an xorg.conf to modify (and none of the files in the .d have the modes listed that I could find).
