Please don't use the X220 or T420 for servers though.. They're the go-to main laptops for many Thinkpad fans because they're so inexpensive and very well-built for everyday use. There are only so many left. I can't imagine using another laptop besides my T420, I'm not sure a better laptop exists and I'm gonna have to take it to my grave if Lenovo doesn't get their act together and release another Thinkpad with a full keyboard.
That being said, good computers going to good people for them is always a good thing no matter the use case.
T430 is fine too, its my daily driver and has the same charger as the T420.
I run SmartOS on another t430 with a cracked screen which has a bunch of guest KVM and zones. Runs ZFS in a mirror and 16G ram, backed by an APC unit for the modem router.
That being said, good computers going to good people for them is always a good thing no matter the use case.