As a 13 owner (only thinkpad 13, nobody talks about it but I think is one of the best pieces of hardware I have ever owned) this would be fantastic. I would love to have my 13 for life. I don't know if my 13 is able to be upgraded like a desktop PC like other thinkpads, but adding a carbon fiber chassis would be like fresh air.
Thermal conductivity?
My comment was referencing the Framework 13, not the ThinkPad :)