What happened to this?

This picture was taken in 2005. Obviously from some building across a GM design center. Or something.
The car pictured looks more like a concept than a production model. There were rumors a couple of years ago about a large Cadillac coupe.
I guess with gas prices, and Cadillac’s decision to cancel V8 engines soon, a car like this wouldn’t fit in the line up anymore.
Too bad…