Yes, I make them.
As for dimensions, I have never really measured them. I know the opening is about 7.25 X 16.5 inches. The inside is big, you can put three gallon jugs of water in the bottom. They mount to the rear two bolts on the fender rail, if the sissy bar covers the rear bolt then it can drilled and the sissy bar can be used as a spacer, others have done it without problems.
If you have any other questions you can email me @ [email protected]