Found this while looking for something else:

"At a whopping 16kg, and measuring over a metre-long, two-year-old Roberto could be the biggest bunny ever.

His owner, Annette Edwards, said: "He can't fit into a normal size hutch, and even has to sleep on a dog's bed."

A Guinness World Records spokesman said Roberto was the biggest bunny they'd heard of, but they no longer awarded records to big animals."

See Roberto here:   Roberto the Giant Rabbit