@Dan_Brunsink It seems to me to be the easiest option. The Compute Module 4 has a small vertical footprint now that it isn’t in the DIMM form factor like the old compute modules. So I imagine it would just take an enterprising group to make an IO board that fits the framework form factor. I do foresee some difficulties however. First I’m honestly not sure if the CM4 is capable of supporting the expansion card system and second the thermals might also be a problem as the raspberry pi 4 SoC runs surprisingly hot. But those things might not be deal breakers for people who just want to run ARM in their sustainable laptop case. Maybe a board based on the CM4 would have its own custom expansion cards also created by the community that wouldn’t be based on USB C but some other system to expand the IO of the CM4 based board. Or at least a way to make the IO ports flush with the outside of the laptop.