Here's a spy shot of the 2012 BMW 6-Series cabriolet model caught on a photo shoot. The second image is alleged to be a cleaned up version of the photo by German magazine Autobild, drawing influences, perhaps, from other sources on the 6-series.
The original image came from e90post.com. The 6-Series cabriolet in the photo appears to be wearing European plates.
What we know of the upcoming 2012 6-Series is very little. The safest assumption is to expect an array of 6-cylinder power plants from BMW's stable of engines.
An M6 variant is also expected sometime after the release of the next-generation 6-Series. It will likely be fitted with a 4.4 liter twin-turbo V8 dialed up to around the 600 PS (441 kW) mark.