After a year or so of wild speculation, Big Jim Ward finally made a formal announcement as reported on Gamasutra.
Responding to a question about what it would take for LucasArts to produce a lightsaber game on Wii, Ward said that the concept is "in place." He added: "We're all over that, and internally we have already played a lightsaber game on the Wii. It's a lot of fun, and we'll get there."
But this may not be the Wii lightsaber game you're imagining, as the blurb for the LEGO Star Wars game for the Wii states "Wii: Motion-sensitive inputs give you exciting new ways to control your LEGO Star Wars characters."
Source: Gamasutra