I just got a 2nd-hand N220, and in attempting to get the backlight control working found your PPA. Of course, I'm also currently trying out 12.10 on it, so I think it'd be great if you could make a build for Quantal. No rush, it only just came out =)
In the meantime I will be fiddling with ACPI settings, if I do find an alternative solution I'll be sure to post back here.Edit:
Aha, thanks to this post here
, the appropriate magic to add to the kernel params is
Odd that it's not working without that, but if it works, it works...