I made it from plastic acrylate sheets, but you could also make it from cardboard. A tip is to use cardboard from a cereal box because it have a large flat surface and is very strong or laminate the print. I left the top open so you could easily remove the Wii mote and also could press the buttons easily. I used few elastic bands to hold it in place. Cause I did not want to make it that your Wii remote would get stuck in it and that you could not take it out again.The handle is a loose in the template from the wii-mote holder because everybody and every age got different sized hands so people could resize that part so that everybody could hold it correct. On the back of the gun are openings so you could connect the nunchuck and the strap.
You need to make own holes for the elastic bands or you need to think of a own thing to hold the wii mote in place.
Download the template here. Please link back if you want to use this template on your website.