@valleyforge wiimote whiteboard was pretty good. I think the latest Linux has support for switch joycons, half of witch have the necessary hardware. I've been meaning to add one to my projector setup but haven't gotten around to it.

@valleyforge
Plexiglass whiteboards that can be wirelessly copied/downloaded onto tablets. Instead of ink, it's stylus pens similar to graphics tablets (eg. wacom pen+touch)