You might be able to remove the imager unit and move it around on paper with a pen.
I don't know who well it would work, it might be very sensitive to the angle between the imager and the surface.
It still wouldn't give you a tablet - they can do things like send the absolute position of the pen rather than just a movement and can sense pen pressure so if software uses a tablet it won't perform the same way with a mouse.
You can get a pen-mouse which are pretty much what you are describing, a mouse sensor in a pen shaped body that look like a mouse to the software.