Now that Congress has voted another $2 billion in funding for the Car Allowance Rebate Systems (CARS) program, better known as "Cash for Clunkers," the program's success means carmakers are starting to face shortages of their most popular high-mileage models.

The latest manufacturer to face a famine is Ford, which is running short of 2009 Ford Focus sedans. The 2009 Focus has been among the most popular vehicles for which clunkers were traded in, along with the 2009 Toyota Corolla and 2009 Honda Civic.

COMPARE: 2009 Toyota Corolla vs 2009 Ford Focus vs 2009 Honda Civic

Employees at the Wayne Assembly Plant where the Focus is built began working 9-hour days last week, and will reportedly move to 10-hour days this week or next week. Ford will discuss its production plans with reporters today.

The changes might add 6,500 extra Focuses to the pipeline by September. Ford ended the month of July with a 25-day supply of the Focus, and stocks have likely declined since then.

The Focus isn't the only vehicle running short; supplies of the 2010 Toyota Prius have fallen almost to zero as global demand for the brand-new third-generation hybrid runs up against a solid limit on the supply of battery packs.

So if you're car shopping from the seat of your qualifying clunker, we have a question for you: How do you feel about, say, a Hyundai?

Clunkers

Clunkers

[Automotive News (subscription required), Detroit News]