SlideControl is a MIDI piano controller, with Virtual MIDI support. It is usually $4, so a nice freebie! This is not the same thing as SlideControl FS, which includes a SoundFont player and costs $10. I haven't played with either.

It looks similar to MorphWiz... and free!

Buy SlideControl on iTunes: Free (On Sale, from $3.99)

Here's a demo from the developer.