Patently Apple has just posted Apple’s latest multi-touch patent, awarded April 27. The patent shows multi-finger chords that can distinguish between a hand in a neutral position and one that is explicitly spread out. For example, the Save gesture uses a neutral hand position while the less common Save As… gesture uses a more deliberate finger spread.
Chords are more sophisticated gestures, but can also have a much steeper learning curve. My guess is that we won’t see these gestures in an Apple product for quite a while since many of them require a significant amount surface area to perform and users are just now getting familiar with the current, much simpler set of gestures available in the iPhone OS products. However, it is interesting to see the rich set of interactions that are possible through multi-touch.
Apple was awarded a similar chord gesture patent(PDF) in 2007.
For a list of current gestures available across devices, see the Touch Gesture Reference Guide.