David Basulto has made a series of Mini Filmmaking Cases with handles for iPhones and iPads that allows you to mount mics and lenses it to it.
David said he made the cases to help his students make better films (he’s a media arts and animation instructor at award-winning San Marino High School in Southern California). He has 4 products available (iPad, iPad Mini, iPad Air, iPhone) after running a successful KickStarter project last year. This is from NAB 2014.