Good idea, but I can see a lot of problems that comes with the idea. First : I seriously think it's a bit late... Second : The cost of it. To be competitive, you will need to sell it to a cheap price, probably less than a 100$ (US). Higher than that, most people will want to go with the alternatives, which are GoPro and Contour since they offer an in-built everything, HD, fisheye (at least for GoPro) and water-resistant component. Third : If you don't actually own an iPhone 4 (I don't have one), it will still be better to go GoPro or Contour since it will be overall cheaper and of higher quality than an iPhone 4 filming. Fourth : POV are just to add to some films, not to film an entire sequence of it. The most beautiful and artistic films are either using 1 or 2 POV shots or none at all, like Life Cycles or whatever. A little boost up would be to be able to lock the head-mount in a certain angle. Right now, as you show in your videos, the angle is not really good as we can't even see the jumps and/or landing. The camera is too high above ground. That's just my 2cents though.

Sorry if it's not a freeride movie but a XC movie showing what our group is all about... Didn't know I had to explain!