I have created a custom cooler for the X1.
Re-used heatsink parts from a old broken asus gpu,
Cpu reaches max 50c with all power limits disabled (13.5 watts) compared to 105c at 11 watts.
This heatsink should be good enough to allow the X1 to survive harsher temparture ranges seen in cars.
Sadly 1 of the usb 2.0 ports is covered but i was not comfterable bending the heatpipe in a way to clear it over he HDMI side instead.