I would build it (probably save some money) but I got so frustrated with my woodworking skills and results on my prototype that I firmly believe someone like me would be easier off carefully outfitting a ready made box.
This is one of 2 boxes I've found. This is the only one i've found within 150 miles that doesn't need internal repairs. They are asking $1250 for it on CL and I've talked them down to $1000. $1000 is far beyond the absolute max I was hoping to spend on an empty shell, so the search continues. As much as I'd love to just go over there and grab it, I don't have cash to waste.