alt Hacker NewsTechnoethical sells a refurbished T400 with GNU Boot.
https://tehnoetic.com/laptops/tet-t400s
Libreboot actually isn't free anymore by FSF standards because it has binary blobs for the Intel Management Engine. Neither is Coreboot which has blobs for many other things. Most modern computers cannot boot without binary blobs for ME, which is why GNU Boot was created.
If you want a modern/new computer, Purism sells them with the management engine "neutralized" but it's still not free by FSF standards because they haven't bypassed it entirely.