One important part here is that it must be able to adapt quickly and easily to the different environment, meaning, network connections, external screens (retroprojectors), etc.
Honestly, the only kind of laptop/system that can do that, are MacOSX Apple laptops. I'm afraid I must say that even with Linux you will often have difficulties to connect to the random WIFI setups you'll find, or to manage the external monitors, etc (and I won't even mention MS-Windows, what a joke).
Oh, and there's also the battery life, 8+ or 10+ hours...
I mean, my main workstation is a Linux box, but as laptop, I use a MacBookAir, because when you're on battery you don't want to lose half an hour of battery time connecting to the network (or losing half the times the hibernation state).
As for keyboard, well, it's laptop keyboard anyways. When working at home, just hook a DasKeyboard or a Filco Otaku on the USB port.
Given your need in pixels, you'd want a MacBook Pro Retina. http://www.apple.com/macbook-pro/specs-retina/
I've worked recently for a year with a Dell laptop with various linux distributions on it (mainly at first ubuntu, but later I switched to debian) and it was quite decent (very nice screen and processor), however it still had those little problem with hibernation, external screens from time to time, switching wifi setups was horrible, and battery time (not mentionning the heat). (On the other hand, I must say that ubuntu works well on a little netbook computer I have around, but of course, I don't ask as much of it as of a development computer (come to think of it, it still had quite a difficult time with a GSM dongle)).
No, really, if you want to be productive with your laptop, use a Mac one.