Although the TSA hasn't come up with anything yet, there is a private company called Clear which provides a registered traveler service. There is a one-time fee and then an annual membership. Once your background check clears and your application is accepted you will need to go to a Clear airport to process your fingerprints before they will issue a card. The big drawback is that Clear isn't available at all airports or in all terminals of an airport. You can
check the Clear website for available locations.