Mercedes-Benz and BMW are both working on a new generation of front-wheel drive compact cars complete with four-cylinder and alternative powertrains, advanced composite construction and soaring fuel economy numbers. However, more often than not, we customers in the U.S. can only dream of such models since in the past they have almost exclusively been ruled out for local sale.

That’s all about to change, however, as both automakers are planning to bring their new compact cars to the U.S. in the coming years to battle tough new fuel economy and emissions regulations. Overseas the cars are described as UKL models, a German abbreviation for lower-compact-class, and in congested urban environments they sell in relatively strong numbers.

The key difference between the incoming new generation of luxury compacts and the cars of old is that there will be plenty of new bodystyles to choose from instead of just the typical econo hatch. Things like sporty coupes, four-door sedans and even a crossover or two are all on the cards for both Mercedes-Benz and BMW.

BMW’s models, of which there are expected to be three, will arrive before the launch of the Megacity electric vehicle in 2013 and will initially be available with a four-cylinder engine. All will be smaller than the current 1-Series range.

Mercedes-Benz, on the other hand, will launch three front-wheel drive compact cars in the U.S. in 2012, all of which will be based on the platform being developed for the next-generation B-Class. There will be a new crossover, coupe and possibly a sedan and importantly, none will wear the B-Class badge. Further down the track Mercedes-Benz is also expected to launch an all-electric compact van.

[Automotive News, sub req’d]