Yeah I have been wanting to pick a Chromebook up for exactly the same thing. I can imagine Arch with Awesome being great on one but it seems Google have made it a pain in the ass to get rid of Chrome OS and stick something else on. While I live in my browser I still work in a text editor/IDE and need a terminal with GCC and other bits. Lenovo have some nice portable machines but, like you said about the Sony, they are bulky.
I would love a Chromebook I could easily install a Linux distro on (I don't mind which, I can work within any distro quite happily although I would pick Debian if I had a choice) with a good 13" screen of 1440x900 (IPS). Don't care or want touch. A solid trackpad with multitouch. All the ports on the left (like this HP) as I am right handed an use a mouse to the right mostly so anything plugged in there gets in my way. A 128GB PCIe SSD. 8GB RAM. 8+ hour battery life. CPU I don't really mind but an Intel i3 would be the best (for me) due to compatibility with everything else. Backlit keyboard would be awesome. I am sure they could do all that for $500 or less. Even if I can't take Chrome OS off and have to dual boot that is fine with me as I quite like Chrome OS for a lot of things and only need a real OS for work. If anybody knows of such a machine please let me know!
Ok I am pushing it a bit with the 128GB SSD but if you stick a standard HDD in there they should be able to keep it at £500 or less quite easily. There are similar spec machines in the 15" range from Acer and others for that sort of price it would just mean scaling down to 13" :)
I would love a Chromebook I could easily install a Linux distro on (I don't mind which, I can work within any distro quite happily although I would pick Debian if I had a choice) with a good 13" screen of 1440x900 (IPS). Don't care or want touch. A solid trackpad with multitouch. All the ports on the left (like this HP) as I am right handed an use a mouse to the right mostly so anything plugged in there gets in my way. A 128GB PCIe SSD. 8GB RAM. 8+ hour battery life. CPU I don't really mind but an Intel i3 would be the best (for me) due to compatibility with everything else. Backlit keyboard would be awesome. I am sure they could do all that for $500 or less. Even if I can't take Chrome OS off and have to dual boot that is fine with me as I quite like Chrome OS for a lot of things and only need a real OS for work. If anybody knows of such a machine please let me know!