this is an extreme ultraking mattress. it’s 12 feet (3.7 meters) wide by 10 feet (3 meters) long.

there’s a place in las vegas that custom makes ‘em and it’s about $85,000 for the mattress, one set of sheets with pillows, a comforter & mattress pad, and one of their bed frames.

standard king is 6’ 4” (1.9 meters) by 6’ 8” (2 meters)

if one were so inclined and had the know-how, one could make their own for about $8,000 … utilizing manufacturing considerations similar in theory to stretch limousine fabrication, of course.