Hmmm. I think the most significant part of this soundboard is the oval channel routed around the perimeter of the top. I first saw one of these on an X braced Taylor acoustic guitar. I don't think their tops are as thick though. It reminds me of an arch top complete with tonebars, but it's flat. Come to think of it, it also reminds me of a Taylor T-5 top.
I wouldn't attempt to replicate this one partly because you would probably have to go through a few prototypes before getting it right, and I noticed there were some luke-warm comments about it in some previous posts. Better to stick with X bracing for steel string.