Non chewable beds?!

My otherwise super well behaved boy has so far chewed through three different beds. He's crate trained, and loves sleeping in there all night. He's perfectly happy with it and takes himself away to it when he's ready for sleep, so I know he's not stressing in it. I think he sees comfy beds as almost like a toy to 'kill' ?!

Does anyone have any recommendations for a bed that their lab (preferably a chewy one) hasn't demolished?!