GM has indefinitely cancelled plans to build a V12 powered flagship sedan in order to move further with plans to build a replacement for the STS and DTS sedans.

It was reported earlier this month that Cadillac has also halted development for the STS/DTS replacement in favor of more fuel-efficient models.

According to InsideLine’s sources, Cadillac has now shelved plans to produce what was known as the XLS sedan (based on the Sixteen Concept) and its V12 engine to focus fully on single high-end luxury model. The sedan is internally known as the DT7 and will be based on the rear-wheel-drive ZETA platform currently used on the 2010 Chevrolet Camaro.

Production is scheduled to begin...