Perhaps check out a local machine shop?
I'm thinking of getting your bog standard industrial metal enclosure the right size to fit my m/b and other pieces (3" tall by about 20x30") and then mounting everything in it.
What I don't know if how I'll make the appropriate *neat* holes in it. E.g. for a half-height PCI card; a hole for a fan grill; the hole for the ATX back plate etc.
Does anyone have any suggestions?