Trey,
I haven't attempted to work that out completely yet but generally I find that if something moves at the speed of light it may simply be because the speed of light places serious restrictions on what we can see.
We may find that gravity only propagates at the speed of light because light is the only way we can observe whatever we are attempting to. If anything goes faster than light we couldnt see it anyways.
There are reputed to be gravitationally bound structures in the Universe that are larger than they could be if gravity only propagated at "c" from the moment of the Big Bang.
These would seem to require a BB-Expanding Universe scenario or a pre-existing field. A pre-existing field requires a pre-existing universe. A big bang could not happen within said pre-existing universe. At least not within currently popular assumptions.
"If your only tool is a hammer everything looks like a nail" If your only tool is light we think everything is visible.
Happy Thoughts, M
-- Updated August 13th, 2014, 6:43 pm to add the following --
I just bumped into this. Hope we can all find it interesting.
http://www.nasa.gov/nustar