Fingertip Maestro offers a new alternative instrument layout. The screenshot is not impressive, but check out the demo!
Update: They sent me a more illustrative screenshot, so I've replaced the original here.
Fingertip Maestro iTunes Description:
Anyone can Play. Fingertip Maestro is an IPAD app designed to make playing the piano and 6 other instruments easy and intuitive. It gives people with no musical knowledge or training, the ability to play convincingly and dynamically, creating music with the feeling and texture of an experienced musician.
For those that can already play, it's a great way to quickly generate chord progressions, riffs and melodies for new songs. With it's intuitive design and great playability, creating music has never been so much fun.
- 7 instruments
• Piano, Acoustic Guitar, Strings, Drums, Bass Guitar, Synth 1, Synth 2
- In-time playing setting (Quantization)
- Color-Assigned Chords
- Chord Name Display
- Tempo Adjust
- Record and Playback
- Export .m4a and Email
- Save and Share to FB, TWITTER, SOUNDCLOUD
- Playable with one or two hands or with someone.