Thank you for your reply. I have always had a deep interest in these larger questions.
Unfortunately, my advanced calculus skills ended up being a C-grade capability, so I’m afraid that the math really does often escape me.
I will definately put my hands on your recommended reading and give it a shot.
Given the issues with C that I mentioned, I wonder if perhaps space actually is a medium, packed with subatomic particles so small or different that we have yet to identify them. Perhaps if they had gravity, but were electromagnetically repulsed by atoms (with a force greater than gravity), this would also solve the dark matter issue. Such particles would be rare close to visible objects, but denser in the space between galaxies. Obviously this medium would have to allow the passage of light generally undisturbed. In this scenario, C might be more analogous to Mach 1 than an absolute limit.
Assuming this medium to exist, this might also affect light wavelengths over extremely long distances, and thus throw off what we think we know about progressive expansion of the universe.
If that is unbelievably stupid, forget it. If it is the hypothesis of the millenium, please cite me. ;-)
I don’t mean to discourage you, but before you reinvent the wheel, it behooves you to understand the wheel.