This August, Alfa Romeo will celebrate its centennial at Pebble Beach, where it is a featured marque at the Concours d’Elegance. Rumor has it that the Italians will cap off the festivities by unveiling the 4C, a compact, lightweight sports car concept. Says one insider from parent company Fiat’s headquarters: “The 8C has been a very successful halo car. What we need next is a more affordable follow-up model that spreads the message over a wider customer base.”

The 4C, interpreted above by our spy illustrator, will do without high-end materials like carbon fiber or a Ferrari-built engine. Instead, it’s expected to feature a highly tuned, 250-hp four-cylinder, possibly mated to a rear transaxle as in the 8C. Production will probably be limited to 5000 (rather than 500) units. The roadster may be followed by a coupe (or vice versa), and prices are expected to start at about $70,000 (€50,000).

For America’s Alfisti, though, the excitement this August, and the 4C, may be short-lived. One would be hard-pressed to call the liaison between Alfa/Lancia and Chrysler a marriage made in heaven, and the crudely badge-engineered Chrysler (Lancia) Delta on display at the Detroit show was hardly a hopeful sign. As far as the Alfa Romeo brand goes, we’re still waiting for a final decision on whether it will return to North America; in January, Fiat chairman Sergio Marchionne said that it will be a year before a decision is made.

For Alfa, which is in a severe sales slump, much rides on the success of the Giulietta, the 147 replacement that’s set to debut at the Geneva show in March and go on sale shortly thereafter. A slightly longer and wider version of its platform will be used for the Alfa 159 successor, which revives the Giulia nameplate and is due in 2011. An Alfa crossover is planned for the following year.

Whether or not Americans see those Alfas, their compact/mid-size platform will come to the States, underpinning a host of Chrysler products: PT Cruiser and Sebring replacements; new versions of the Dodge Caliber, Avenger, and Nitro; the Jeep Patriot and Compass; and a still-nameless Chrysler crossover. The cross-pollination works both ways. Both Alfa Romeo and Lancia stand a good chance of obtaining new rear-wheel-drive flagship models based on the next Chrysler 300C and built in North America.