There are few commercially available software solutions that include end-user-modifiable head shapes for industrial design. We did, however, find a few resources that may be useful to you. This one seems more game-character oriented, but the heads look reasonably realistic, so perhaps there is more to this solution than just visual aesthetics, although we could not find any evidence of that.
Also, we tend to use Turbosquid when we need representative geometry that the client either does not have or is not allowed to provide. For example, if we need a drill press, computer workstation, robotic arm, etc., a quick search on this site typically provides a good quality 3D model for a lot less than it would cost to build it ourselves or hire someone to build for us. Since we can import geometry from any source into our products, this is a cost-effective approach we’ve used for many years. The point here is that the Turbosquid site also includes human heads, and some of them are based on bodyscan data so if you find head geometry on Turbosquid that fits within your target anthropometric design boundaries, this could provide a solution either within your design environment – or within ours, if there are human performance criteria associated with the head-worn equipment designs, of course.
Finally, this page contains a variety of links (some head geometry-related) that may be useful to you.
One of our contacts at a University that teaches kinesiology, ergonomics, and human factors said that while there does not currently appear to be any commercially available solutions, this is probably going to change as head shape is becoming an important topic.