Ok, here's my latest try.

I've about got it where I like, but as you can see, it's still not quite right.  Instead of the "white foam edge/", I'm getting black or some crazy dark color.  The problem is that the water plane intersects into the sand (to give it that curved edge) and I assume the raytrace bias of refract node is the cause, but I don't know how to fix it.

Also, the sand's poking through a bit.  I'm going to try adding a u_texture node to better control the height of the sand's cellular.  Better suggestions are welcomed. ;-)