Well, the list of computers you can install libreboot on is growing ->
http://www.libreboot.org/docs/hcl/index.html#supported_list
The greatest thing about the gluglug's X200 however is not libreboot but the
fact they managed to successfully remove ME and AMT, the Intel's Management
Engine system, and Intel's Active Management Technology firmware, thus making
a truly libre laptop (a one that is not backdoored) and a hardware that truly
respects your freedom.
And this is why AFAIC there is only the gluglug's X200 out there and all the
rest is just standard hardware you can NOT absolutely trust. All the rest is
just "free software friendly", that is to say works with a 100% libre OS, aka
"laptops with a wifi adapter that requires no non-free firmware and an
integrated INTEL GPU for 3D acceleration, if you need 3D acceleration.."
https://www.fsf.org/news/libreboot-x200-laptop-now-fsf-certified-to-respect-your-freedom
cheers!