Exotic Cadillac XTS mule spotted

Autoweek reader and frequent spy-photo contributor Spencer Abbott brings us these photos that he took last weekend in Birmingham, Mich.

The photos clearly show a heavily camouflaged Cadillac XTS. But given that production-ready examples of Cadillac's new full-sizer have been making frequent appearances on Michigan highways for months, the heavy camo on this XTS is a bit puzzling.

The bodywork looks identical to that of the production cars, though some of the trim pieces and badges are absent. The Cadillac's headlights and taillights are obviously not production pieces, and most of the car is painted in primer, with the plastic pieces of the body bare. In fact, the only parts of the body that are really obscured by the camouflage are the lower sills, the hood and the windows between the C- and D-pillars.

The cameras or sensors suction-cupped to the rear fenders seem to indicate that this XTS mule is working. So the hypothesis that it's just an engineer tooling around in an old mule seems unlikely.

When the Cadillac XTS Platinum Concept made its public debut in 2009, it was a plug-in hybrid. Could we be looking at a powertrain mule for a hybrid XTS?

By Rory Carroll