Joining the ranks of The Gap and Dell, Mercedes is venturing into the Group Buy arena – allowing consumers to club together and buy its diminutive Smart car at a group discount (-22%) off list price.

Trialling the group-buy deal in China, on the “Juhuasuan” group-buy platform of China’s largest e-commerce site Taobao, Mercedes sold 205 Smart cars in 204 minutes on September 9, 2010. Not bad, considering Mercedes usually sells only one Smart car a day in China.

Even with slashed margins per vehicle, the increase in volume sales may have made the deal worthwhile for Mercedes as well as their happy new customers (the Smart car usually retails for RMB175,000 (US$25,750) in China, with the group buy deal offering the car for RMB135,000 (US$19,860)).  And then there’s the publicity.  According to People’s Daily, the first car was sold in 24 seconds, 55 cars were sold after six minutes and 205 cars were gone after three and a half hours.

So two questions: 1) When will Mercedes roll out Group Buy in the US and Europe?  And 2) When will a startup step up to create a US/EU version of Taobao’s “Juhuasuan” group-buy platform to host these deals?

If Groupon is the fastest growing company ever – selling group-buy vouchers for low value goods and services – just think about the potential for a group-buy platform for big ticket items?