I have spent a lot of time searching the internet, and this is one of the most similar concepts that I have found so far. Chris Eckert has created a beautifully designed piece which, while it looks better than anything I plan on creating, is essentially a limited version of what I am attempting.
His design doesn’t take into account the form of the human arm and is drawn on a flat plane where it assumes his arm is. This is limiting because it doesn’t allow for different size arms to use it, but also means that it can only draw on a very specific region of the arm. His design also uses predetermined symbols, rather than letting the user design exactly what they want on their arm.
Hopefully I can take some of what he has learned and apply it to my project. He has a blog which gives updated on the project on a week to week basis, but unfortunately it never goes into too much detail. The blog can be found here.
Kurt is another example of a similar project, but this one was created 8 years before Auto Ink came out. This design allows for the wearer of the tattoo machine to draw a symbol on a Palm Pilot and then that symbol would be drawn on the persons forearm. This design is a lot more similar to what I am proposing, just at a very rudimentary level.