As I mentioned in a previous thread [0], I upgraded an old X61 with a custom mainboard produced by a group of enthusiasts in China 1.5 years ago and never looked back.
Damn the bezel around the keyboard is so sexy on that machine. That's exactly what I would want but no one sells something like that off the shelf with a warranty. I still rock my X230 but the display is garbage.
[0] https://news.ycombinator.com/item?id=18273305