There are a couple control mechanisms supported by other rhythm games but not Clone Hero.
Rock Band / Guitar Hero Vocals
There are no plans to include support for any microphone or vocals, however lyrics are displayed in game (if provided in the chart).
Rock Band Keyboard/Piano
There are no plans to include piano/keyboard support
DJ Hero Turn Table
There are no plans to include support for the DJ Hero Turn Table
Nintendo DS Guitar Hero Grip
There are no plans to include support for the Nintendo DS Guitar Hero Grip from Guitar Hero: On Tour.