In the world of $400,000-plus ultraluxe convertibles, things are rather volatile. Or at least it appears so, as the Bentley Mulsanne Convertible teased in concept sketches last year will not be built, according to the brand's CEO.

Speaking with Car and Driver, Bentley boss Wolfgang Schreiber said the concept, when shown to a small group of Bentley owners last year, didn't arouse enough interest to justify its construction--despite the killer lines of the long, tall convertible.

The problem? Not the look or the feel, but the breadth of its appeal. Only some parts of the U.S. and Europe would want the drop-top luxobarge, implying the sunny, fair-weather areas where a convertible to be seen in would appeal to the upper crust of the One Percent. That translates into too few sales even by Bentley's exclusive standards.

On the other hand, another famously unloved Bentley concept car does appear to be headed toward production (although with some modifications to better suit the aesthetic preferences of its clientele): the Bentley SUV, previewed by the EXP 9 F concept last year.