I have done this two ways. When I did this last, we made a life cast out of the actor's head/face. Then made and painted a latex false head. Our closest seat was 6 feet from the stage, so we took a lot of care to make it as realistic as possible.
The whole process was pretty easy, and not as pricey as I thought. The most expensive part was the chemicals that are mixed to make the latex. The most time consuming part was the painting. Then we just put a wig on it. It looked great.
When I did it in college we used a styrofoam wig head, then wrapped layers and layers of masking tape until we got the right size and shape. Then painted and wigged it. Would not have passed at 10 feet, but from 25+ feet in this theatre it worked really well.
Super cheap, this. Easy and fast.
Original Message------
Anyone ever made a head for Macbeth? How did you go about it?