Since 1984, Jon Barnes has been carrying tourists through Aspen in the back of his 1978 yellow Checker cab. Now he’s carrying thousands more virtual visitors online. The vintage taxi is enough to stop traffic. But over the years, Barnes has been accumulating more and more cool stuff — electronic keyboards, drums, lasers, lights — until by the early ’90s, it became more a vehicle for entertainment than transportation. Now, the Ultimate Taxi is on the Internet, broadcasting images of passengers and Aspen scenery through a cutting-edge wireless network, designed by Harvie Branscomb with Sun Microsystems Aspen research lab funding the wireless broadband project.