I'm typing this reply on an X220-4290-CZ2, a bog standard laptop. The 1366x768 screen goes very bright and I find it useable in sunlight on e.g. a train in a seat by the window when you can't move out of the sun. This is at 52 degrees North mind you, might be different further South.

I have an X60 with slackware on that just runs and runs and runs. It is the screen that I find the limiting factor as OA mentioned. I might summon up the confidence to have a go at the LED backlight hack...

There are non-tablet variants with IPS screen. It's also easy to swap the panel so you can buy it separately if you don't find a good offer.