I want this as a MetroCard, with the circled 1/2/3 and 4/5/6 written in the usual NYC subway colors.

Looks like the author has it under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License and so the work is to be used it its entirety only. So I guess if you do make a modification you can't distribute it.

I could see this being used in a fun little puzzle game or something. Different tapes or finding the right starting point on the tape to end in the correct place, etc

True, but I'm a bit concerned about generalizing the Halting problem to public transport.

Let's see Paul Allen's Turing machine