I still like the idea of using a carb mani flange and some close fitting tubes and plenum and TB from a port efi car. You'd still have to fab fuel rail and stuff (if the donor won't fit) and injector bosses, but this is much simpler than welding up a whole intake, especially with the water necks incorporated in the manifold - using the carb flange saves all of that.

Getting other injectors to fit the Starion TB may be a little tough - I understand that they are a unique size.

Not responsible for advice not taken...