Just perusing this topic and a gestalt of ideas stole upon me and clobbered me with a pipe wrench... (sorry if anyone thought of them first, I was only perusing when mugged).

Black T-shirt with white lettering

Front: The Beetle (with flaming tires and speed lines) beneath "We kick ass in a 4-cylinder kind of way"

Back: The Beetle (from behind) below "Behold the angry wizard put-put-putting away..."

-Dev