A mate of mine has started producing Metal Panniers and top boxes. They're the same dimensions as the Zega stuff but considerable cheaper yet with thicker metal.
Check out his site if you're interested:
http://www.transenduro.com/
I think they come with which ever puk is needed for your racks (H&B, Givi etc.) I saw some the other week and they're proper solid and really well made, either silver or powder coated and I believe they can make bespoke changes as per your requirements.