Recent filings with the United States Patent and Trademark Office unearthed by Motor Trend reveal that GM has applied to register the nameplates Cascada and Calibra here in America. Intriguingly, it has filed the trademarks through the Opel division itself, and not through Buick or one of its other North American brands, but it's more likely that the General is trying to cover its tracks rather than contemplating relaunching the Opel brand in the US.
The Cascada name is currently in service on a four-seat cabriolet which Opel sells in Europe and Vauxhall does in Britain, and which Buick has long been rumored to possibly sell in North America. But the Calibra name hasn't been used in over a decade. It previously referred to a coupe based on the Opel Vectra, and was also sold by Holden in Australia and Chevrolet in South America. Just what (if anything) GM plans to do in America with a nameplate that isn't even in use overseas remains to be seen, but the prospect of a Buick coupe (whether based on the Cascada or otherwise) doesn't seem out of the realm of possibility. Of course, GM could simply be protecting its intellectual property with no intention of actually selling any two-door Buicks in North America, but we'll just have to wait and see which way the wind blows.