Something on the cheap that might work for you for your battery box is at True Value I found little black plastic garbage cans for $2.99, ones like you'd use in an office or bedroom, actually pretty nice thick black plastic that cuts with a box knife or tin snips. Making a small case out of acrylic sheet and using Dap plastic adhesive to glue the black plastic to the outside, it looks similar to black shrink wrap but is more rigid and looks pretty nice, the plastic has kind of a black matte finish, not glossy. I think it would be possible to make a case out of 1/4" plywood and cover with the black plastic stuff for a decent look, some protection and waterproofing.