You can buy raw shells online from manufacturers such as Keller. Go on eBay and search for 'Keller shell" and you'll see what I mean. Then you have to drill the shell evenly for the number of lugs you have. It helps to have a drill press. Takes some time too. you could make a 24" kick thats 24" deep.
I'm pretty sure you calculate the lug spacing by using 3.1415926 x r / number of lugs. I don't remember exactly.
He's located in Nashville, TN. It used to be in Jackson, TN but I guess the timing was right for him to move to Nashville, so this past November/December he moved the store.