Same results in kernels:
* 2.6.32.8 vanilla
* gentoo-sources-2.6.32-r4 (above + gentoo patches)

All tests in attached output from vanilla kernel.

I have searched for similar bug reports, and didn't find anything that helped.  I have attached a tar'd bzip of all debug information I've collected that seemed to be asked in other similar reports.
--> Contents of tar:
dsdt.bin
lspci-tv.output
nomodeset-find_proc_acpi.output
nomodeset-find_sys_class_backlight.output
vendor-find_proc_acpi.output
vendor-find_sys_class_backlight.output
vendor-find_sys_class_backlight_sony.output
vendor-manual_attempt_to_change_brightness.session
vendor-xbacklight_attempts.session
video-find_proc_acpi.output
video-find_sys_class_backlight.output
video-xbacklight_attempts.session

I have a fairly new Sony VPCS111FM.  It's pretty much an Intel-everything laptop.
--> see lspci-tv.output

I cannot change the laptop brightness.  From what I can tell, it looks like Kernel Mode Setting is required (?) on this machine/chipset to get X started, as I get a blank/black screen w/o KMS (using xf86-video-intel-2.9.1).

I have attempted to use the kernel parameter "acpi_brightness" set to either 'vendor' or 'video', and have attached various outputs that show the contents of /proc/acpi and /sys/class/backlight under both cases.  'vendor' gets me further, as the 'sony' directory and subentries appear in /sys/class/backlight, but they do not change the physical appear of the brightness of the screen.
--> see vendor-*

I have also attached a binary DSDT dump.
--> see dsdt.bin

I'm happy to try anything, as I'm completely at a loss after much debugging and trial and error.