"while also outputting enough power to handle the Graphics Module with a discrete GPU"

Oh? This is news to me. Will it have an nVidia graphics card?

the 16" will have a slot for discrete cards (I don't think it will be a PCIe slot but could be wrong).

No need to wonder or guess, according to The Horse's Mouth[0], the expansion bays in the 16 will have a PCIe x8 interface. (Not to be confused with the expansion cards from the Framework 13.)

[0]: https://frame.work/blog/introducing-the-framework-laptop-16

Thanks, I remember seeing that, but wasn't sure of the form factor (eg I am not sure you'll be able to plugin any old gpu).

It's not a desktop PCIe slot on the back of a laptop, but the interface is already documented. The electrical, shell-fit PCB, and general form-factor specs of the 16" laptop's expansion bay are already published under a CC-BY license by Framework: https://github.com/FrameworkComputer/ExpansionBay

Direct link to the pinout PDF: https://github.com/FrameworkComputer/ExpansionBay/blob/main/...

It's a 4th-gen x8 interface, so there are limits to what "any old GPU" might be capable of performance-wise, but creating a passthrough-port accessory seems possible.