Oh my friend has one, we refer to them as Loads. Buddy, her load, is HUGE close to umm 195 lbs. and he isn't overweight. He is a sweet boy and mostly sleeps. She just rescued a great dane puppy and says that Lucy uses him as protection from her other dane when she gets to rough with her.
He's about 6 years old and a rescue. Very tragic story actually, his owners were in Newfoundland on some rocks and fell off the rocks into the sea. People found their cameras and there was only 2 pics on it of them on the rocks before they fell in, their bodies were never found.

Anyways here's some pics of Buddy.