I've been buying custom-sized/thickness foam to put in my dogs' crates from these people for years: http://www.foambymail.com/ I cover it with comforters from the thrift store for ease of washing, and replace every few years.
The last time, I also got one of their 5' diameter round dog beds stuffed with shredded foam for our two GSDs. It has been a HUGE hit. It's very thick, and easy to fluff back up if the dogs make a divot.
My old girl sleeps on this bed. It's self warming instead of a plug in bed which safety first DH likes. It's very cushy and huge. She is a 13 y/o lab with a lot of joint issues. She also sleeps with a fuzzy blanket over her every night.
I just got this one for our 15 year old ACD mix. She cannot get onto the couches or beds anymore and needed a comfy place to sleep. She's not a fan of dog beds in general, but seems to really like this one, as she spends a lot of time on it. It is really very nice, especially for the price.