It would probably be blasphemous so you could keep it as the original, but I think the Demotivator of Optimus Prime that reads "*Facepalm* - Shut up... Just... just stop. Please. My head hurts." with a picture of Jesus facepalming would probably work too. Then again, like I said, if it's too blasphemous, then just keep the original.

That said, I saw a picture of one used at a counter-protest for a production of The Laramie Project that said "God Hates FarmVille." That one made me lol.