A card is selected and signed. You tell the layperson (you call them "layperson" to their face, because you're cool like that), that their card will change into another card while under their hand.

They place their hand over the card. You do something to affect the magic. When they lift their hand, their card has changed - into your driver's license card. Except where your picture should be is now a small image of their card. Weird.

You take out your wallet and find their card where your license should be, thus doing your card-to-wallet routine which, as recently ruled by Congress, must be included in every card act (lawbreakers will be placed against an official wall and killed in a hail of thumbtips).

On turning their signed card over they see a tiny picture of you in the corner. Is this original? Should I get some sleep?

As far as I know this has not been done before. It sound like a fantastic effect. it has all the elements of a great routine. Stay up all night if you have to cause the creativity is flowin'!

Especially if you could make their own drivers license and card transpose out of their own wallet.