You have got to be kidding. That looks terrible and wastes half the space on the screen. It's not even very good skeuomorphism, the drop shadows aren't in a consistent direction, and the layering of the brushes and canvas doesn't make sense.
Note how the wet paint mixes up on canvas.
More on mixing colors: http://www.youtube.com/watch?feature=player_detailpage&v...
This app is really the best skeuomorphism out there.
The rest of the UI is an abject travesty.