A source has stated to Ars Technica that in lieu of an actual piano attachment to Rock Band 3, a Keytar will be provided instead. A Keytar is exactly as it sounds, an electrical guitar that utilizes piano keys rather than strings. The attachment is most likely going to be made by Madcatz, who is handling the entire official set of "instruments."
This same source has also stated that a “pro mode” will be added into the game. This new mode will enable players to play “proper technique, and may lead to actual skills on guitars and bass.” Given that the game uses buttons, it will be interesting to see how this might play out. Ars Technica believes that this could be accomplished by the creation of instruments that mimic true to life incarnations.
The rumors of the new piano/Keytar instrument started with the Green Day: Rock Band demo on Xbox Live, and it has gotten gamers in a frenzy. With the anticipation of another round of full-on music genre games coming by the end of the year, the sales slump might turn for the better.
The Keytar and Pro Mode are not confirmed by MTV and Harmonix, so take this report with a grain of salt for now, but gamers need not wait too long as E3 is right around the corner.

