There are also pictures floating around of a model where the wiimote is the barrel, and the nunchuck is incorporated into the err... bit you hold with your hand. Could one of you native speakers remind me what it's called btw? Anyhow, the nunchucks triggers fitted very well where a pistol's trigger would be in that one.
Of course all of these would be pretty impractical with any games except for rail shooters, and even with those if you need to use the other buttons like A, 1, and 2. Hopefully developers will be inspired by Brawl's example and include a high degree of control customization in their games.