Thick 2" maple amp platform--couple or isolate?

What about a sandwiched platform: Corion, 2 inch maple, and an MDF or high grade 3/4 inch marine plywood layer in the middle? Or some other variety of heterogeneous layers, possibly bonded with epoxy.

George, no I have not heard anyone constructing stands with heterogeneous materials sandwiches. Here are a couple of related ideas for composite platforms:
1. Timbernation offers already some nice stands made from a triple layer of 1 inch thick maple boards, running front to back. The idea of the multiple layers is of course to break the continuity of the grain hence reduce sound wave propagation. One possible improvement to this concept is to turn the middle layer at 90 degrees, thus with the grain running left to right. This should further increase rigidity and further dampen vibrations.
2. Related to the previous idea is simply to take several sheets of marine grade plywood and bond them to a thickness of 3 to 4 inches. As plywood is formed by multiple crossgrained and bonded layers of wood veneer to start with, the resulting composite structure should prove extremely rigid and well dampened.

George, my local wood crafting supply store in Austin (Wood Crafter (512-407-8787) sells Baltic Birch plywood sheets 3/4 inch thick for $35. A single sheet can be cut into 6 tiles measuring 20 x 30 inches. All of them can then be sandwiched together to form a single platform 4.5 inches in thickness. I defy anyone to make such a beast resonate. . . at any frequency!
An interesting variant would be to bond this structure to a top sheet of Corion. I am expecting a call from Dupont today with some pricing.