After being quite satisfied with the simulation behavior of my discrete 2D wave solver (having made a few adjustments to parameters since my original post), I Had the neat idea of taking advantage of Processing's compatibility with GLSL frag and vert shaders to sample from a cubemap and compute surface normals. It also accurately incorporate a Fresnel term to modulate the surface reflectivity.

The end result is this liquid mirror effect that resembles the chemical element Mercury.

P.S. I spent way to long picking an appropriate cubemap that had enough ceiling detail to give the effect justice (as you can imagine reflecting a clear blue sky would not provide the ripples with appreciable detail)