Rockband 3 to add piano?

After finishing the Green Day: Rock Band demo the above picture shows the standard Rock Band bass, drum, guitar, and mic icons, but as you can see there is also what appears to be a piano icon.

What does this mean for the franchise?  What will the set list look like for the next game?  Only time will tell, but I think Stevie Wonder (Better than has been previously done with this one hopefully), Ray Charles, Elton John, and other great pianist could easily make their way in to the music gaming fray with this new instrument.