Look on ebay. They have a number of Acopian A12MT series available. Since this is just a box, I would open open your search for other suitable 12V supplies with same or better specifcations.
The economy must be doing a lot better! Has anyone else noticed that used bench power supplies are going for five or more times what they sold for last year. I troll for ones that need repair. Non working supplies that would cost me $50 last year are now going for $350.