copper roof vent

Does anybody have a source for a kitchen roof mount exhaust fan? The kind that has the blower mounted on the roof. It needs to be copper. The one I need to replace is 18 wide by 32 long. I'm removing a shingle roof and replacing with a copper roof and want to install a new copper fan. I can't seam to find what I need. If all else fails I could make it using all the internal parts of the old one, but that would take time to do.

Copperman, If you don't find what you are looking for but are only going for the aesthetic value any way, just clad it.

I checked that site out but that's not what Im looking for. I need a kitchen exhaust fan with the motor in the vent housing on the roof

http://www.volko.com/copperatticfan.htm

Got a feeling you're gonna build that one! Sorry.