Jonathan,
You wrote: "We may have been held back by too often assuming that Minkowski's assumptions about the time dimension are inseparable from SR. But a theory can be absolutely right without its interpretation being right, and only the core of SR has been confirmed by experiment."
Has it? The core of special relativity is shielded by what Lakatos calls "protective belt":
http://bertie.ccsu.edu/naturesci/PhilSci/Lakatos.html
"Lakatos distinguished between two parts of a scientific theory: its "hard core" which contains its basic assumptions (or axioms, when set out formally and explicitly), and its "protective belt", a surrounding defensive set of "ad hoc" (produced for the occasion) hypotheses. (...) In Lakatos' model, we have to explicitly take into account the "ad hoc hypotheses" which serve as the protective belt. The protective belt serves to deflect "refuting" propositions from the core assumptions..."
Without the protective belt ("contracting lengths, local time, or Lorentz transformations") the Michelson-Morley experiment would have unequivocally confirmed the emission theory's tenet that the speed of light varies with the speed of the light source (c'=c+v) and refuted the assumption that the speed of light is independent of the speed of the light source (c'=c):
http://www.amazon.com/Relativity-Its-Roots-Banesh-Hoffmann/dp/0486406768
"Relativity and Its Roots" By Banesh Hoffmann: "Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether."
Pentcho Valev pvalev@yahoo.com