Well, that was a quick response, you might say. Less than a month after a dealer starting taking deposits for delivery of plug-in hybrid Priuses, that dealer is now returning them to the customers. What is clear is that Toyota clamped down on the plan, which the dealer—Magnussen’s Toyota of Palo Alto, Calif.—said was simply a way of responding to customers who wanted to make sure they were first in line for the promised plug-ins. Twenty-five customers had sent in $500 a piece to have a shot at the future Prius.

The problem is that Toyota has not announced any retail timetable for sale of the plug-ins. Irv Miller, Toyota’s Group Vice President, Corporate Communications, praised the dealer for “doing what we’ve always encouraged our dealers to do… to listen carefully to their customers and try to meet their needs,” and for deciding to return the deposits. While promising to bring the plug-ins to the retail market as soon as possible, Miller added that “It just may not happen as quickly as we’d all like it to happen.” Toyota has promised only to have several hundred plug-in Priuses in fleet operations for testing by the end of 2009.

Felix Kramer of CalCars, a plug-in hybrid advocacy group that had trumpeted the deposit program, responded to Toyota’s move by imploring the company to “expand its limited fleet evaluation program planned for 2009 into a larger demonstration program that makes cars available to early adopters and more corporate and public fleets.”

The plug-in Prius may be coming, but it looks like it will arrive based on Toyota’s internal timetable, not the whim of eager customers or dealers.