For those of you that don't know how the sensor bar works I will explain. When you turn on your Wii, it communicates with your Wiimote the same way that an Xbox 360 talks to its wireless controllers. All that the sensor bar does is use infrared to triangulate where your Wiimote is. The only reason that your sensor bar is connected to the Wii is for power.
So now for the replacement. See candles give off infrared. So if you set up two candles above or below your TV at the same range that your sensor bar black spots are, your Wiimote should still work.