Finally got around to putting together a USB powered Wiimote Sensor Bar. 4 IR LEDs dissipated 4.8v forward which is close enough to the 5v coming off the USB port. Cut up some old circuit boards as a base for each side and Velcroed them to the lid of my 17" MacBook Pro. Used my old Sony DCR-PC5 to check that the LEDs were indeed firing. Nice remote mouse control for the computer via DarwiinRemote.