If your going to rely on a gimmick deck like these people are suggesting to you to "save" you, please do yourself a favor and just go for the invisible deck. You get a great trick, and if you screw up and easy way to "come back" i.e..."this isn't the card you picked? Weird? What was it? Are you sure??? You didn't see me go into my pocket, or use anything but these cards here, did you? Well that's strange because in my other pocket I have another deck of cards, and look...one card is turned upside down..."
You go whatever way you want to go with Invisible Deck. It can be a quick and easy lifesaver (I admit, Ive had a couple screw ups where Invisible saved me).
Now, THAT is an excellent idea! You've made it seem as if that was your intention the entire time and not some cheesy attempt at covering a mistake by getting a laugh (Which I've done more than ONCE). That's possibly the best out for a card trick that I've heard yet.