I understand that there's a huge difference between people and magical items, but the focus of this is on creating permanent magical enhancement on prosthetics itself and seeing how far you can push it.
For example, say you have a PC who's lost an eye and is looking to replace it with a prosthetic eye... could they have truesight permanently cast upon the eye to give it usefulness and grant the user partial truesight though that eye? Or for a smaller example, have a special magic cast on a prosthetic arm to regive the user a sense of touch through that arm?
In other words: Are prosthetics too permanently attached to a player character to be considered a potential magical item?
EDIT: I've discovered Ersatz Eye, which kind of answers my question, though I am still wondering if such magical items can be further enchanted, or if their name removes such an ability?