German publication Automobilwoche reports the S-Class Pullman limousine will be manufactured in Bottrop, Germany, from December 2015 by Brabus, a private company with a long history of tuning Mercedes-Benz, Smart and Maybach vehicles.
Both Brabus and Mercedes Benz parent company Daimler have declined to comment on the report.
Late last month, Bloomberg reported the Mercedes-Benz S-Class Pullman would be the largest series-produced passenger car in the world, measuring approximately 6400mm from nose to tail, making it roughly 400mm longer than the extended-wheelbase Rolls-Royce Phantom.
The report also claimed the Pullman would feature armour plating and three seating rows, with four seats facing each other in the rear separated from the chauffeur by a partition window.
The S-Class Pullman will be designed to meet the demands of markets such as China, Russia and the US, where extra-large, ultra-luxury limousines are hot property.
The Pullman will top the S-Class family above the forthcoming extra-long-wheelbase S-Class Maybach variant, which is tipped to debut in November at the Guangzhou and Los Angeles auto shows.