Are you sure you want metal? 110mm soil pipe and extensive range of fittings are widely available.
Axi plastic blast gates will glue into the end of the pipes and provide a convenient adaptor to 100mm flexi to the machines.
I've run this system for a good few years now and no issues with static.
If you want metal, one company that comes to mind is, Ductstore, they have online catologue. If you for search spiral wound duct, you will find several suppliers.
Martin