Would MacBook Air help you? I'm really happy with how well windows runs and integrates on my MacBook Pro. Might be an option for you as they're nice machines.
Perhaps, but unlikely. From what I gather, Linux doesn't yet play nice on the MBA, which is a shame. If that story changes significantly in the near future I would certainly consider getting one. (My current machine is a white C2D Macbook, triple-booting OSX, Windows and Ubuntu)
EDIT: actually, checking the documentation here: https://help.ubuntu.com/community/MacBookAir4-2
paints a much more rosy picture than I remember, maybe it would be a viable option.
I'm running Ubuntu 11.10 on a MacBook Air [1] right now - much to the consternation of my IT department - and it works mostly-fine. The install was a bit fiddly and installing kernel updates breaks it, but both of those are due to needing to patch the kernel, which apparently is no longer needed for Ubuntu 12.04.
Day to day, the battery life isn't as good as it is in OSX, but other than that, it pretty much just works.
[1] (4,2 I think, but I can't remember how to check.)
It was kind of a pain to install Ubuntu on a MBA, but I found everything except the trackpad drivers worked pretty well. And this was a year ago -- I'd assume the situation has improved.
