The only models in question would be the hard drive based models. There will be no problems with the iPhone, iPad, iPod nano or shuffle. The iPad case uses these same magnets.
They do a very good job staying how you place them. If you didn't wrap them and threw them into a bag you will have problems but if you neatly wrap it before you toss them into a bag they will stay nice and neat.
They are currently patent-pending. We are working with a manufacturer who already produce headphones. They make a range of models from cheap, average quality headphones to expensive high quality models. We can incorporate this design into all of them.
The headphones will work in non-Apple devices. The compatibility is for the attached mic/remote. The microphone will most likely work in other devices but the remote probably will not.
These headphones are the standard issue Apple headphones but we could release a higher quality headphone with the same magnetic cord. As for the weight, the magnets are so small they make it only slightly heavier, about the weight of a quarter. From our testing there is not much difference. The magnets secure the split cable under your chin so they stay in place while running.