There used to be an old laptop that had this. And integrated mouse that you could pop out and use, the pop it back into the laptop case when not needed.
It might be kinda neat to have a expansion module that did something similar. When not used, the mouse is tucked away as an expansion module. Click a button and it pops out and little mouse (likely shaped like the expansion module housing ) and wired into the expansion module connector. When ya are done, just click it back into place
Bonus if you can do something like this in collab with swiftpoint
It certainly would be a fun expansion card to have. Though given the small size I’m not sure how many would use it much. So Framework might not want to invest in stocking it. Feels like more of a community expansion card.
For a wired mouse, which it seems you were suggesting, QMK has full mouse support. Though there is a limited number of optical mouse sensors that have available drivers. I converted my Steel Series 15 button mouse over to QMK and I love it. There are a couple QMK forks that supports the nrf52 series BT chips. BlueMicro is one.
What might work is a trackpoint that folds into a drawer inside the module. Pull the drawer out and the nipple snicks upright and locks into position. Press a flat button (part of the bottom surface) to unlock, bend the trackpoint down into its drawer and push drawer in. Electronics can go beside the trackpoint bed.