I really see the 4G modem in the Pyra as being more about 'on the go data' and not so much about 'telephony'. Some day it might be possible to take/make calls from it, but I don't see that as a 'primary usage case' for it.
I rarely make calls.
And if I do it's mostly Telegram.
Looks like there is a single CSI lane broken out to a connector on the main board so maybe hacking in a camera will be possible if there is some room to squeeze it in, there are some pretty tiny cameras these days (I might have a go at this if a spare case is cheap enough if I ruin things).
I already have a tiny 5MP USB camera module.
It's mounted on a 2,5x3cm PCB.
As there is so much unused space on the Pyras Display PCB I have plans to cut out a whole where I can fit in the camera.
I also habe a USB-hub PCB at the size of my fingernail.
That one will also fit somewhere.
I want to solder it to one of the USB connections on the main PCB and from there one way to the camera and an other to the USB-port.
That way I don't loose functionality and when I turn off the USB-port it the camera should also need no power.
If so, there is some additional room in the housing where the touchscreen is placed.
I can add a physical switch for the power line of the camera there.
The Pyra lid should be thick enough so that the camera won't stick out.
I need some protection for it but that will be done last as I need to see how everything turns out at the end.
If it works, it won't be suitable for nice photographs, but for a quick shot it will do the job.