Hey mate, Thinkpad X220. Screen's a bit smaller than you mentioned. Mine's i7 model, with the 9 cell battery. It has great compatibility with Linux, and i get 6 hour battery life, but not much more. I have always upgraded my kernel to 2.6.39 so suspend to ram works. This is the first time i've read about this battery issue and coincidentally i'm actually running Slack atm with the 2.6.37 kernel (which i haven't done much testing on) and i've just looked at the battery monitor. 80% 7 hours 41 minutes
hope this helps, Thinkpads are expensive laptops, but they really are great.