Any update on this?
Also, what about a CM4 expansion bay module?
A CM4 expansion bay module could be basically a second computer inside a Framework 16.
It might not even need to use the PCIe or full power capabilities of the expansion bay, just DisplayPort (for the internal display), USB (for communication between the mainboard and expansion module), and 5v 2.5a (enough to power the CM4 without needing voltage conversion from the 20v line).
Some software implementation could be setup to send the keyboard/trackpad inputs over the expansion bay USB to the CM4. USB tethering could share the mainboard’s WiFi connection over that USB connection (the 480 Mbps of USB 2.0 is good enough for the average internet connection IMO). And some hotkey could enable quickly switching the mux and keyboard/trackpad between the mainboard and CM4 module.
This is probably the module that I would be most likely to buy (currently am just getting a shell, which this could slot into). Having a full second computer (even a CM4) inside my laptop that I can switch to seems very cool and useful IMO.