I've got a fairly similar package, designed to notice secondary pointing devices, create master pointers to allow them to be used simultaneously, and calibrate them.
The primary use so far is to support my packages to allow the use of PS Move controllers and other attitude-sensing devices as primary mouse pointers using direct pointing. I've pushed the code to https://github.com/kdienes/xinput-pointermanager … I'd be glad to contribute to your work or to refactor to work alongside it.
