Thanks, everyone, for the comments -- here's a quick stab at all the questions in the above posts.
Ian: Concerning inflation, it's certainly widely accepted, but that only means that the *problems* with it have been widely rationalized as acceptable, not that there aren't any serious problems. The biggest point in inflation's favor was a "prediction" of scale invariance of the CMB (although this prediction actually arose before inflation ever existed). But this central point in its favor has now been dealt (i.m.o.) a crippling blow by research pointing out that such scale invariance should occur even without inflation; see http://arxiv.org/abs/gr-qc/0205058 .
Your other main point, that experiment needs theory to tell it where to look, is a very good one, and I certainly did ignore that in my essay, if only to stress that *some* theories can leave experiment so far behind that they aren't really physics anymore. But I also obliquely made your point, in that my (largely theoretical) discussion *did* imply where experimentalists should focus their efforts (on measuring the time between consecutive measurements, and on time-like hypersurfaces). Still, when one is talking about ultimate (i.e. all possible) measurements, having theory tell you "where to look" is largely irrelevant: the ultimate experiment will look *everywhere*. (Of course, it's easy to talk about measuring all measureable quantities -- the hard part is actually doing it!)
Finally, your comment about variational principles not having enough information is exactly my point. However much information you need to solve initial-boundary-problems, you only need half as much information on the initial portion of a variational problem. Of course, it's easy to envision problems where neither case has enough information to solve the problem, but there's no case where you have enough info to solve (and verify the solution to) a non-variational problem, but still not enough info to solve the corresponding variational problem.
Mark: Certainly everything one is measuring is constitutively local, in my view -- but (this the the key point) the measurement itself is non-local, in that it spans a finite region of both space and time. All my so-called "non-local" effects come from this non-local constraint on local "constituents". I have a pathological aversion to the concept of constituents that somehow obey non-local equations -- I can't see how they could possibly work in a GR-compatible framework -- so I haven't given them much thought.
Terry: You're absolutely correct that if my premise of a 4D block universe is incorrect, then my conclusions will be incorrect. The conflicts between QM and the block universe are discussed in Ref. [1], and I think that choosing the block universe formalism over QM's formalism is the right path to resolve the "mysteries" that you mention. As for whether our physics has erred by not taking our experience of "now" into account... I have the exact opposite view. We've erred by taking it into account more than we should have! Despite the fact that "now" doesn't show up in our equations, we insist on squashing our 4D universe into 3D states that purportedly describe everything there is to describe. The reason QM and QFT are built this way is because our brains instinctively think in terms of "nows". In my opinion, we need to fight this human instinct to make progress -- it's the way that our brains think about time and causality that create all these "mysteries" in the first place.
Philip: As much as a revolutionary as Barbour is, I think he's building on a faulty foundation -- Einstein, I think, was one of the few people to see where the proper foundation should have been built, but even he couldn't quite give up on the idea of solving everything with initial boundary conditions. As for "non-local hidden variables", you might read my response to Mark above. It all comes down to what is meant by "non-local", but as I see it, the ultimate physics theory won't contain any variables any more non-local than, say, the E and B fields in Maxwell's equations. Few people would say that these were non-local... But if you impose a future boundary condition on the equations, then the E's and B's at any particular point in spacetime "Q" now depend on that future boundary condition. And the fields at another point in spacetime, "R", depend on the same future condition. And now there will be interesting correlations between the E and B fields at Q and R, seeming "non-local" correlations that can't be explained by virtue of what has already happened. Does that mean that the E and B fields in Maxwell's equations can be transformed into "non-local hidden variables" simply by putting future boundary conditions on a system? It depends on what you mean by that phrase. Maybe it's just safer to say that I think that all physical variables will solve local field equations, and leave it at that.
Thanks again, everyone, for all the kind comments.