The HP ZBook G1a is similar to a Macbook in case(*), touchpad, screen and audio quality, design and performance - just the efficiency and battery life are kind of crap and, uh, I haven't figured out yet how to configure reliable sleep on Linux. It lasts 6-7 hours idle. You can also empty the battery in an hour with heavy compile jobs, but that one Macbooks do as well according to info I've found on the net.

(*) Aluminum is more about perceived than actual quality - I wouldn't mind touching something with lower heat conduction, especially in winter. The only thing that I really like about it, compared to a Thinkpad, is the stiffness of the screen part.