Got MacOS X 10.6.8 fully working on my old Vaio P11Z.It is very stable & pretty much everything is working.
I've updated from SL 10.6 using this kernel http://www.mediafire...0rb9f8an9bgl6wk and doing a backup of the previous IOATAFamily.kext and restoring it after the update (without rebooting of course).
For sleep, search for SleepEnabler.kext.10.6.8.zip it should work. Backlight is not working like in your case. I wonder if Lion or even Mountain Lion can work on the Vaio P using the patched kernel. I will first backup my hard drive and try the update ;)
Oh and the Appstore is working also but you have to apply the software updates first otherwise you will get an error message :wink_anim:
Is Flash working on your Vaio ? Mine shows a black screen with delayed sound.