there isn't an app that i know of, but you can make it so when you press the power button when you are recieving a phone call it will answer the phone for you.
Hmmm I might be able to make that work.. is that just a general setting? (I'm puting our dx into a prop, and am using it to drive the sound when called.. I have another app that will play a video during a call, and the goal its to have the phone ring with a farnsworth (Warehouse 13) ringtone, and then display a video loop on the screen in a farnsworth prop.