re: Paradox ??
You state that:
One can change a photon's vector- and I guess one could call any change of vector as acceleration.
Seems like a interesting and perhaps a testable theory.
We know that gravity can bend a beam of light, or as you say "can change a photon's vector," since this has been proven to be so, it follows that if your assumption is correct, then the photons that travel past the gravitational field will have higher speed than the photons that do not encounter the gravitational field.
Would this beam that was bent be travelling faster than the "constant."?
A moving mass is accelerated in a gravitational field, why not light.
You also wrote:
Photon don't accelerate [or can be accelerated] as far as I know. A photon can be made to go slower [I.e, through glass].
A photon can be absorbed, which means that it will cease to exist in its original form, and I suppose that if the energy remains in the absorbed material then the speed of the wave packet must be slower than the speed that it entered the material.
Conversely when a atom emits a photon, the wave packet must accelerate to the constant speed.
That is the way I see it anyway