I know that there are companies out there that make a aftermarket plenum chamber for the zetec that use all the old ford parts but do not have any links to them, or if you have any plans of how to make one that would be better

have a look at this picture, it is home made, looks pretty simple. If you e-mail dutchsuperseven he might send you the drawings for it. I have got them somewhere will have a look later.
Rescued attachment mvc-002f.jpg

thanks stu that the picture that got me looking at this. If you find them drawings that would be cool

When someone fabs a plenum like this, do they blend in some sort of air horn where the indvidual port enters the plenum tube?