Does any restaurant in America have a wireless credit card machine?

I got a note from reader ‘S’ who enjoyed the recent ‘America’s dire handset marketplace‘ post and commented thus:

When you pay by credit card in a restaurant they still don’t have GPRS/EDGE/Wi-Fi readers that they can bring to the table. Why not? What a massive business opportunity.

I was thinking that too. They still take the card *away* to the wired card machine. Surely the suppliers must be readying wireless terminals?

Or are they waiting to properly deploy PIN first?