Chromebooks or macbooks are your best bet. I believe top of the line Chromebooks are actually very good. If you put Linux on them they'll be very capable.
Don't buy a Chromebook for linux. While driver support usually isn't an issue, the alternative keyboard layout is terrible for most applications. To even get access to all of the normal keys that many applications expect you need to configure multi-key shortcuts which varies in complexity based on your DE. In most cases it will also void your warranty because of the custom firmware requirement.
That's true. I did see a video of some developers making top of the line Chromebooks run Linux, you may need to do further research on it. Check out if your device is supported :