Trouble is I haven't found the source code to actually do this sort of thing, though my hunch involves inferring positional data using either acceleration or velocity data from the accelerometer, smoothing the data out using a Kalman filter and then modifying the X-Y coordinates of the mouse using that data.
Something like that could work; the only problem is that you are only getting acceleration data, and not true x/y positional values - I imagine that error might accumulate quickly, but it is certainly worth trying. I can't find the link, but I remember running across a company that was selling 3D position tracking sensors that connected to a PC via USB (and sold for $99.00 US) - they seemed to do something like you're describing, so it is certainly possible (but finding an example that works the same might not be - for the reason that it is a very marketable product).
One method you might try, though not wireless, is to feed a self-retracting line through a hollow shaft/handle analog joystick (using gimbaled x/y potentiometers). On the axle of the line retraction mechanism, you can mount a multi-turn potentiometer (maybe with gear reduction), or a quadrature-encoder device. Then, by using these three sensors and a bit of geometry/trig math, you can calculate the 3D position of the end of the line on the retraction mechanism; mount a small ball on the end of the line to grab.
Alternatively, you could also mount the end of the line to your wrist, and then attach a joystick handle, or a "wired glove"...
You might also be able to get yaw/pitch/roll info from a device like this one:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1231185714
...incorporated into the handle or glove.
Something to know about the device I described - there was a company that at one time sold such a device to hook up to the PC; I doubt that there is a current patent on it, but it might be worth searching for if you are concerned. I don't know if it would be an issue for the project you are planning to do or not. For personal use, it shouldn't be an issue, and you might come up with improvements (as long as you're not selling the item, it shouldn't be a problem - but then again, I am not a patent attorney!).
