You're dog will thank you! I have a Mastiff and a Great Dane and have been through my share of dog beds. Mammoth dog beds are by far the best. They are designed for XL dogs with a focus on comfort. Lots of foam to cushion big bones! They also come in a variety of sizes & colors & the covers are removable for washing! You will get years of value out of these beds. I hope you are as happy with them as I have been.
It sounds like you really love your dog! We had the same with our Irish Wolfhounds ? searching high and low for a good bed he could actually fit in. We don?t have any children so we do everything for our dogs. A few years ago we found this site - http://www.bigdogbeds.com/ - which allows you to customize a bed. We got the largest size which is a bed 62? inches wide (over 5 feet) and 82? inches long (almost 7 feet), and then 8? deep. However, if you want a round vs. a rectangular bed they have those too. Every bed is custom made ? so we got to pick the color of the fabric and everything. They?ve had great customer service ? and all their products are made in the USA.
Not only did I find some good suggestions on big dog beds, but there were also some helpful articles on how to pick the right one at http://www.bestbigdogbeds.com/ . It helped understand why George 125lb Great Dane (named that due to the constant "Watch out for that..." as he grew! lol!! ) would benefit from it and how to get him one he could fall in love with! Good luck on your search!