Welcome!
You can use the camera on the wiimote to triangulate - we use it in various applications here...
You have to mount 3 LED's in a triangular fashion(not planar) and then feed the positions into your application - the only problem is to tell which one is which... unless you pulse the LED's there is no way to determine this...
You can pulse a LED with a simple chip and hey presto

As example: If you pulse 2 out of 3 LED's the one that is not pulsed(constant on) can be upwards - feed these pulses into your application and then you know.
This whole setup assumes the wiimote to be stationary...
Of course I'm just thinking loud..but I think this is the best way to go.
Good Luck - UndCon