I was looking for mention of industrial gas turbines in the HOMER information sections. Is HOMER appropriate for this equipment, or only smaller devices?

HOMER can certainly model industrial gas turbines, compare their economics to other alternatives, and help determine optimal sizing.  But it might not model them to the degree of detail that you desire.

For example, HOMER assumes that all generators have affine fuel curves, meaning the graph of fuel consumption versus power output is a straight line with some y-intercept.  That may not accurately model a gas turbine.  Also, HOMER does not calculate inlet or outlet temperatures.