AppleInsider reports today on an extensive patent, titled 'Magnetic attachment unit' filed by Apple last year on connecting external accessories to iOS devices (typically the iPad), through magnets. This is similar to what the smart covers and cases do now, but this patent is an 'omnibus' in the sense, it covers everything from iPad cases to wrist straps to even other iPads connected to an iPad! Remember that this is just a patent application and very few or none of these concepts might see the daylight. But going through the list of applications Apple cites as examples, like connected touch covers, keyboards, car and treadmill mounts, etc., definitely makes it an interesting read (USPTO).
Oh by the way, as AppleInsider points, out towards the end of the patent application, there is the mention of the 'iRing' or a ring that could modify or add specific functions while swiping over an iPad like device, using 'Hall's effect'. This might not be the mythical iRing that was rumored as an Apple iTV accessory, sometime back (TheFrustum) and though Tim Cook joked about a high tech Ring made by Apple (AppleInsider), this patent suggests that this concept has at least (theoretically) crossed Apple's mind!