Hi Paul. I completely agree that I see no reason why you couldn't "get a functional human out of a brain scan" --- though even there, I probably wouldn't convert my failure to see such a reason into a bet at more than 100:1 odds that there's no such reason. (Building a scalable quantum computer feels one or two orders of magnitude easier to me, and I "merely" staked $100,000 on that being possible --- not my life or everything I own! :-) )
Now, regarding "whether there can be important aspects of your identity or continuity of experience that are locked up in uncopyable quantum state": well, I regard myself as sufficiently confused about what we even mean by that idea, and how we could decide its truth or falsehood in a publicly-verifiable way, that I'd be hesitant to accept almost ANY bet about it, regardless of the odds! If you like, I'm in a state of Knightian uncertainty, to whatever extent I even understand the question. So, I wrote the essay mostly just as a way of trying to sort out my thoughts.
Scott Aaronson has a new 85 page essay up, titled "The Ghost in the Quantum Turing Machine". (Abstract here.) In Section 2.11 (Singulatarianism) he explicitly mentions Eliezer as an influence. But that's just a starting point, and he then moves in a direction that's very far from any kind of LW consensus. Among other things, he suggests that a crucial qualitative difference between a person and a digital upload is that the laws of physics prohibit making perfect copies of a person. Personally, I find the arguments completely unconvincing, but Aaronson is always thought-provoking and fun to read, and this is a good excuse to read about things like (I quote the abstract) "the No-Cloning Theorem, the measurement problem, decoherence, chaos, the arrow of time, the holographic principle, Newcomb's paradox, Boltzmann brains, algorithmic information theory, and the Common Prior Assumption". This is not just a shopping list of buzzwords, these are all important components of the author's main argument. It unfortunately still seems weak to me, but the time spent reading it is not wasted at all.