Seriously, I wouldn't bother. It makes no sense.
The Chromebooks available are dirt cheap, good-looking, light-weight, run for 8 hours and longer and have their OS tailored to light-weight power-saving CPUs and built around the computers it runs on - sorta like Apple. Chromebooks basically are the poor mans mac-book air. And if ChromeOS fits your bill and you have no problem with your OS basically being a remote extension of the todays online service known as Google you should go right ahead and one of those available. That current one from HP looks pretty neat, for instance.
As for the dabbling, I'd go exactly the other way around: Get a ready-made buy-unpack-works Chromebook and install Crouton on it for Linux freedom pleasure. Don't be silly and try to build your own. It will be shitty, lots of work, short on battery life, weigh a ton, look like crap and be expensive in comparsion.
Mind you, I did just get two refurbished ThinkPads for Linux progging and fiddling, but those are definitely not meant for lugging around. They each weigh well over 2kg and run 4 hours on a full-charge at most and are power-hogs in compasion. Good for proggin C/C++, running LAMP at full throttle (ones got 18GB, a Quad-Core Intel iSomething in it with a 256GB SSD) or playing Fallout 3 on Wine with the GFX all maxed out.
I do *not* use them for everyday utility computing though. One actually serves as ... a server (duh) at work.
My everyday computing, mail and leisure surfing I do on a 10" Yoga 2 Android tablet. Even lighter than a Chromebook and runs 18 hours under full load. ... Have you thought about something like that? That might actually be an alternative. Although ChromeOS does seem to be a better fit for your useage.