No one on this planet comes close to what the Sultan of Brunei (family) when it comes to car collections. He has a whole collection of one-offs from Ferrari (incl sedans and station wagons), Aston Martin, Bentleys (includes SUV), Rolls-Royce etc. These manufacturers used to call on him every year to present custom designs, usually made in batches of 6. It has been said that his business helped bankrolled Rolls-Royce from bankruptcy in the 80s.
I think he has them parked according to color in his 3-5,000 underground parking and has dedicated technicians on standby. I also read somewhere it could take up to a couple of hours to retrieve a car parked way back. He also has a collection of winning F1 Cars and Sir Frank Williams used to drop by every now and then for a visit.
Just insane
but every enthusiasts fantasy. His fully stocked harems doesn't hurt either