Back in 2003, GM made a huge statement at the Detroit Auto Show when it introduced the Sixteen, a 1,000-hp 13.6-liter V-16-powered luxury-boat designed to flash a little Caddy heritage in the form of the Sixteen nameplate and V-16 engine. While the exterior was a little derivative of more plebeian Caddies, this concept was quite literally the Cadillac of Cadillacs.

Step inside, and you were invited into a warm, luxurious leather interior with walnut and aluminum accents. Equipment like the Bulgari dashboard clock, silk rugs and crystal emblem on the steering wheel appeared straight out of a Rolls Royce or Bugatti order book as opposed to GM headquarters. The concept was most definitely light years beyond any actual production cars coming out of Detroit.

Unfortunately, while there was some rumor and hope of production, the car was never approved. Like so many other imagination-stimulating concepts, it was retired to the proverbial museum of concepts past, forcing us to accept the XTS as the ultimate in Cadillac.

But rumors are pointing to not one but two super-XTS Cadillac models in the coming years. According to a report from Car & Driver based on discussions with Cadillac insiders, GM's luxury brand wants to start competing upmarket. It is considering developing a new, rear-wheel platform--codenamed Omega--which would underpin a flagship sedan in the vein of the Mercedes S-Class and BMW 7-Series. The car would have six and eight-cylinder engine options with a possible hybrid following at a later date. Launch could happen as early as 2014.

That's interesting and all, but the really juicy tidbit from the report is that GM is also looking straight past BMW, Audi, Mercedes--straight at the likes of Rolls Royce and Bentley. The company is rumored to be considering a possible competitor for the Rolls Royce Phantom, and that competitor would undoubtedly borrow generously from the Sixteen concept--though hopefully they'd do more with the exterior than just tart up an XTS.

Despite the fact that the Sixteen was designed to close down cylinders depending on driving conditions to deliver better efficiency numbers, I just don't see a 13.6-liter V-16 engine cutting it in today's market--even the ultra-premium market. But perhaps a more modest bespoke V-12 is in Cadillac's future.

Perhaps not. We fear that this rumor is likely to go the way of the last ultra-luxury Cadillac rumors. Even Car & Driver had difficulty telling the tale without a bit of tongue hitting its cheek. 

But that won't stop us from hoping...

[Car and Driver]