I googled for a while and I think you are out of luck. This is possible, but apparently no one has done it.
If you want to use your laptop's keyboard or mouse with another computer, you can use hidclient for linux.
As for the Wii, there are many libraries that allow you to use the Wiimote to control your computer, but none to do what you pretend. You would have to implement Wiimote's client protocol by hand.
If you are interested in writing it, the WiiBrew wiki has lots of information on the Wiimote. I have also found some info about Wiimote emulation at www.wiili.org (which is down, but can be accessed via web archive): someone wrote a little program to change your computer's HID descriptor and communicate with the Wii, but there are no further developments.