Just for a bit of fun, I attempted to and successfully got CM:Touch working on my iPhone 4S.
Its actually quite playable and haven't had it crash on me yet. Given the smaller screen area the sensitivity is a bit too high, making moving the camera a bit difficult. Moving units around is also a bit challenging, especially as the unit icon is covered by the commands menu once you select a unit.
Anyways, here's a short vid.
http://youtu.be/g3R3d-dnotU
Can't wait for CM:T 1.2, hoping for an official iPhone release