I own one of the factory Cadillac Limousines...
1976 Fleetwood Seventy-Five Nine-Passenger Limousine. Has power-operated glass partition window, jump seats & footrests, rear radio and climate controls.
Black with black leather up front and black crushed velour seats in back.
Wheebase is 151.5" and overall length is 252.2" (just over 21 feet). Weighs 6,040 lbs (I had it weighed.) I bought it in July, 1999 with 59,474 miles; now has about 98,000. 9-12.5 mpg. 500-cu-in engine.
It is really fun to own and drive a limousine! Lots of room inside, the rear compartment is almost like an apartment! Quiet and very smooth ride.
Here are some photos.