I will hopefully be backing my big lad very soon and need brushing boots for him. He has 10" of bone. Which brands have larger sizes than full please as they are a little snug.
Also Le Mieux do some really nice ones and Equilibrium might be worth a look. Premier Equine do (or did) a size they claim is XL but I found they came up too small for my big wb.
I second the trizone ones my boy who also has 10 inches of bone takes the XL size although he can get away with large on the front at a push. Also the premier equine XL and Xxl boots are a good size.