Other programmers who seem super-productive to me include Julian Seward (bzip2 and valgrind), Larry Wall (patch, rn, and perl), Ken Thompson (Unix and substantial parts of Plan9 and Golang), Aaron Swartz (web.py, Open Library, Demand Progress), Steve Wozniak before his accident (Apple I, Apple II, Integer BASIC, a hardware video game, SWEET-16), of course Bill Gates (BASIC-80 and various other early Microsoft products), Niklaus Wirth (Pascal, Modula-2, Modula-3, Oberon), and maybe Darius Bacon, although none of his free-software projects are widely used.
None of them approach Bellard's level.
I think Bellard has another important thing going for him, beyond discipline and followup: he tackles important and difficult problems, things that are barely within anybody's reach. He's mostly not working on another text editor, another online chat system, or another casual game.
Who are your candidates?