An all new four-wheel drive, Corvette Z06-engined, BMW M5-baiting Cadillac CTS-V will become the flagship of the re-launched US brand’s line-up next year - but Autocar has learned that US bosses have yet to approve the car for right-hand drive production.The snorting 500bhp CTS, previewed by the CTS Sport concept shown at this week's SEMA show in Las Vegas, is still under development in the US. Over there bosses remain unconvinced of the financial case for exporting the super saloon to the UK, despite Cadillac bosses here fighting for the car to be imported as hard as they can. US bosses are worried that the limited number of cars likely to be sold in right-hand drive markets doesn’t justify the millions of dollars needed to engineer the car properly for them.If the new CTS-V is four-wheel drive, unlike any CTS gone before, the nature of its all-wheel drive system may make it all-the-more expensive to convert for right-hand-drive. All-wheel drive versions of Mercedes' C-class and BMW's 3-series, with a front-mounted engine and rear-mounted transaxle gearbox, require an extra driveshaft running forward from the transmission to the front wheels. In left-hand-drive models, this is routed through part of the front passenger footwell, and makes converting to right-hand drive prohibitively expensive. The same could be true for the new CTS-V.However, a decision to bypass the UK market with its halo CTS could still be interpreted as proof that Cadillac still doesn’t take Britain seriously, and given this week’s re-launch of the struggling GM luxury brand, that's exactly what the firm doesn't need.