Hi Steve,
you can develop the Atem Driver by your own. If you need assistance you can ask here in the Forum.
If you can’t do this, you can ask someone to do it for you. But usually this cost a little (depending on the guy who will do this)
If you have a driver for the Atem, it would be great if you share the code here, then I will put it in the next release.
I’m currently very busy (until 12 June), but I can support you after my Job is finished.