A new Wii? That certainly is vague – but completely plausible. Sony has changed the PS3's lineup multiple times since its release - though it hasn't helped sales much - and Microsoft has made many changes over the life of the Xbox 360. Nintendo has remained fairly static with their offering probably because if something is working great there's no need to mess with it, not to mention they have barely been able to keep up with demand. However, there's still tons of room for improvement – DVD playback appears to be the #1 request, among others which Nintendo has claimed at some point they want to include.
Given their willingness to “theme” items in the past, like the DS Lite, it's possible it may be a simple superficial change. Regardless, I cant help but wonder what Nintendo has in store.