Heyho guys,
a while ago I uploaded the read-edid.tcz extension with a script monitor_modes in it, which returns display data values of supported modes.
The next step is to ask Xvesa -listmodes about the modes of the gfx card. Find the greatest common value of both and use it ;-)
I tried it with my 1920x1200 LCD display and at least I get 1600x1200 instead of 1024x768!
So usage:
1. put vesa_max_res.sh to /opt/
2. replace 1024x768x32 with $(/opt/vesa_max_res.sh) in your .xession file
3. backup /opt/vesa_max_res.sh and your .xsession
Feel free to report fail or success, might be useless to some or most
Cheers
Robert