Quote - On the other hand, consider an individual requesting a custom head morph not having prior written consent to use mentioned likenesses in public/private galleries.  Such actions can lead to cease & desist court orders and/or lawsuits if inappropriate images are generated. 

And this is the main point. Without a model release form, any artist that takes on such a job is taking a big risk, regardless of the intentions of the client's request. Lawsuits aren't worth the 50 to 100 or so you might get from such a commission.