For those who feel limited by the approximate 35mm focal length of the iPad's lens, the Padcaster comes with the Lenscaster, an add-on bracket with a 72mm threaded mount for attaching lenses. A 72-to-58mm adapter is included, too, as well as a cold-shoe adapter, two 1/4-20 screws, two 3/8-16 screws, and a custom camera mount screw (more on that later).
If you simply want a wider or longer lens, there are inexpensive adapter lenses you can attach, such as the Vivitar wide-angle adapter in the picture above. If that's not good enough for you, you can attach a 35mm lens to the case, though getting it to work correctly isn't easy and you'll need at least a depth-of-field adapter. But, if you're after a shallow depth of field for your iPad videos, it is possible and there are instructions (and warnings) on the Padcaster site on how to set it up.
Apps, such as Filmic Pro for full control of the iPad's video capabilities and for editing, and accessories like the Apogee Jam (pictured above) for connecting an external mic are what transform an iPad into a mobile video production lab. It's the Padcaster that brings them all together, though.
Lastly, for anyone who shoots video with a digital SLR, you can remove the flexible urethane insert and the frame can be used as a dSLR cage. Just mount your camera in the center and you can start attaching whatever accessories you need around the outside of the frame.