Oh man.... this will be interesting.

Similar to how nervous system does their custom? Check it out.

Nervous System Customizer

Thinking about placing lenses within a 3d print sounds annoying and is expected to be a manual step. But thinking about it, many types of ornament could be used and applied by hand with wax.

This is just a very basic illustration; personally I think this could be fun but doesn't have the professional repeat-ability I am interested in.