Without a doubt the most eccentric and wealthy of coachbuilding's patrons is the Sultan of Brunei,
His Majesty's majesty is a collection comprised of several thousand cars.
In the '90s the royal family accounted for nearly 50-percent of all Rolls-Royces sold, but that's just the tip of the proverbial iceberg.
The Sultan owns the racecars driven by each F1 world champion since the 1980 season and a stable full of the most exotic supercars. But the crown jewels, so to speak, in the Sultan's collection are several unique custom-built automobiles, including fully roadgoing examples of several concept cars – such as the Bentley Java and the Pininfarina Ferrari Mythos – and a fleet of sedans and wagons based on the Ferrari 456 GT.
Topping off the list is the Ferrari FX, a specially-commissioned supercar based on the F512M.
Via http://www.autoblog.com/2007/07/21/autoblogs-top-10-coachbuilt-supercars/