Crazy Eddie wrote:
Which is what a modified Minkowsky space would be: a metric suited for transformations on objects large enough to curve space around them.

It breaks down as soon as you bring strong gravity into the picture.
Crazy Eddie wrote:
Am I incorrect in my belief that physicists have spent an impressive amount of time trying to arrive at a unified field theory that would render special relativity superfluous, or am I misunderstanding something here?

Far from it. Most of the work I do these days involves the use of special relativity to study the physics of QGPs produced in heavy ion collisions. Trying to replace special relativity would be futile because it's an important part of modern quantum field theory.
Any kind of unified field theory, if it even exists, would include special relativity as it would need to be able to retrieve the results of quantum field theory on nongravitational backgrounds.
Crazy Eddie wrote:
Moreover, I am under the distinct impression that the FRW Metric is used primarily in bigbang cosmology to describe the expansion of the universe from a point singularity and describe the movements of all galaxies as a whole and is inherently inapplicable on the small scale. Am I wrong about this, and if so, set me straight.
I am also under the impression that the Schwarzchild metric accounts for gravitational time dilation between higher and lower gravitational potentials but not inherently the angular velocity or relative of any two objects in different orbits of a gravitating mass. IOW, time dilation due to relative velocity is not included in the Schwarzchild metric. Am I wrong about this, and if so, set me straight.

FRW describes cosmological dynamics on the largest scales and equations for both cosmological expansion and the movement of cosmological dust and fluids can also be derived.
Schwarzchild describes the dynamics of bodies on the astrophysical scale in and around spherically symmetric objects (that is, black holes, stars, planets) and is the source of the gravitational time dilation equation. In the instance of the GPS, there's dilation due to both the effects of special
and general relativity, as confirmed by the HafeleKeating experiment among others.
You'd probably find it quite interesting to go and read about these yourself, as a) the forum does not support LaTeX and b) I don't have the time to fully explain all of this, most of which can be
found elsewhere.