> If Framework opens this up for other companies to make modules

From what I can tell, they already did that: https://github.com/FrameworkComputer/ExpansionCards

> USB port module with an integrated Logitech wireless mouse receiver

This guy seems to be making something like that (minus the USB port): https://www.youtube.com/watch?v=0_uOzNt-xwY

People are working on some interesting stuff. Example:

RP2040 expansion card: https://community.frame.work/t/rp2040-microcontroller-expans...

The engineers at framework seem to be very active on the forum engaging with the community.