I have 2 ideas how to improve wiimote functioning.

1, problem with IR diode, if u r looking for a strong IR laser, try use some from old cd-rom. Its possible to remove optics and use wide area realy strong laser for a pen.

2, like a pointer its possilbe cheap green laser pointer. Green lasers have with green light very strong IR beam. All Chinesse cheap lasers dont have IR filters included. Price for cca 10 - 20mw laser is about 15, 20 USD. Problem can be with eye protection, more than 5 mw is dangerous for the eyes.

Did somebody try it?