My initial thought was to simply include the electronics required to attach the Wii to an arduino or other microcontroller. This has been evolving in my mind to include a version that outputs directly to two servos. This would make the module very useful for canned applications like camera/sensor tracking.
It will not be difficult to produce this additional module pre-loaded with the required code. Some inputs such as PID values and sensitivities will need to be included. Either a USB or LCD interface would be required. This is all very do-able and would be really useful particularly for art or video production projects.
One immediate thought is that it would be useful for projects like this:
The skydiver would simply need to have a IR LED to allow for tracking, although the sun might be an issue at times. There may be ways around this as the Wii IR camera outputs the 4 brightest points. The sun may be disproportionally brighter and able to be ignored.