Has anyone used Deltron enclosures? They're slightly cheaper and slightly larger than a 1590B. They're at Mouser part# 400-4591.
You can try to find a retex enclosure, they are easy to find in Europe (made in Spain) and cheaper than Hammond!
Where do you find them?
In Italy they are distribuited by Melchioni, you can see www.retex.es for more information, I think.