Another idea: Instead of actual tactile dots, use a voltage between two appropriately sized/positioned contact points, high enough to be felt by the fingertip, but not so high as to be uncomfortable. Then you just manufacture it as a regular PCB.
(It would probably be required to multiplex the voltage between different dots, so that the finger current always flows within the small area of individual dots, rather than between dots.)
It might work, and it's an incredibly simple solution, but I'd want to check out if there is any chance of long term nerve damage. The user will be using it many hours a day nearly every day.
(It would probably be required to multiplex the voltage between different dots, so that the finger current always flows within the small area of individual dots, rather than between dots.)