I was looking for a cover for my Masterbuilt XL and found that Masterbuilt doesn't make one. So, someone on this forum suggested trying the The Cover Store at www.the-cover-store.com . I couldn't find the thread again so I can't given proper credit to the person who suggested it. So, thanks to whomever it was!
I purchased the 32" x 32" x 40" smoker cover style 146. The Masterbuilt XL approximate dimensions as I measured them to the outside of the handles were 29" W x 23" D x 44" H. It was a little large but gets the job done.
This how it was packaged.
Here are some before and after photos. As you can see from the side view, it is a little large front to back but not too bad. At least it's covered and not too difficult to install. It has an elastic opening so you have to stretch it over the smoker box but it stays nice and tight once completely installed. It doesn't go completely to the ground so leaves and junk won't get trapped under it as well!
Front View Side View