[Gary Boldwater]

Lorentz contractions would be relative to the preferred reference frame. Search on "quantum foam" and "gas filled Michelson interferometer" for some fun reading.

Some things that are not relative are acceleration and radiation. If one accelerates charge, it radiates (not in every case). If I accelerate relative to stationary charge I don't see the radiation.

[Oberon]

Lorentz contractions would be relative to the preferred reference frame.

Under the currently accepted model, they would. If your previous conjecture were to prove viable, however, all reference frames would not necessarily be created equal. In fact, C might cease to be a scalar, if I'm reading you correctly.