Here's my solution, sorry for the iphone pics, I'll try to post improved ones later.
Mine is slightly "undersized" in relation to the depth and width of the sub as I wanted to create a stealth, "floating" look once it's atop of the base. I'm stacked 300+lbs on it with nary a creak or disturbance.
The base lengths/rails are composed of 1 1/2 square stock poplar with a 2" center block for added stability. The top is a piece of 3/4 laminated pine. You could use oak or whatever you like, but I was painting mine black anyway and have found a small piece of lam pine to be amply strong when properly supported. All this, nevermind the fact that you hardly see it anyway once the sub is mounted.
The pads atop are much more rigid/susbtantial than they appear. Then I also have plastic threaded inserts tapped into the poplar base that further isolates resonation.
The adjustable steel feet have "glider" caps that finish the damping and also work amazingly well sliding it around like it's on ice.