xorg.conf is not overwritten at boot
yes it does
You don't tell us which version of Mint
6 (i don't think mint relased a minor version, anyway i don't know hot to get the exact version
in the later editions you have an option to "fix X" when you boot in Recovery mode
in my version i don,t have this option (well I added it) I only have "full boot", "compatiblity mode", "memtest" and "boot from harddisk" (or something like that).
About "fix X", it should overwrite the xorg.conf for a basic one right? anyways this is not what I want. Maybe somewhere it call this feature. This can explain why i always get this damn basic version.
By the way, after each boot i can get the "old version" because it do a bakup ( xorg.conf.<full time>)
Furthermore you don't tell us if you have Mint installed on the USB stick or if it's the live CD on a stick
Hum well... you are right to ask it. The first time i tought I installed mint, but in fact it should be the live cd on the usb stick with the persistent mode. (ho, is it possible that the livecd overwrite from 0 some stuff? it could explain also why log file seem to log only the current boot)