If removing DRM doesn't work, maybe adding an alias to load the apm module will? I noticed a couple of places right before X started up, where the log file said "unknown module char-major-10-134", and the character device with major 10 and minor 134 is /dev/apm_bios, which is the apm.o module.
Perhaps adding an alias char-major-10-134 apm to modules.conf and running /sbin/depmod -a might help? I sort of doubt that, but it's a slim possibility.
Could you attach a log.txt from dmesg as well?