How thin is too thin?

I’ve been debating whether to roll the dice on a flex shape using 1.5# stringerless EPS and bamboo veneers on the top and bottom.  I’d compensate for the loss in volume by adding some width and length.  The plan so far is:  6-4 x 14"n x 21"w x 16"t, with a 2" max thickness via slightly concaved deck and a performance foil/rails and a quad setup.  Overall volume would be about 32 liters or so.  For the veneer I am considering using the 1/64th rotary cut bamboo stuff that Gary Young uses on his boards, one layer on the bottom and two layers (verticle+horizontal) on the deck with a 2oz fiberglass deckpatch underneath.  The exterior would be a single layer of 4oz top and bottom with no extra reinforcement on the rails.   Alternately, I might try 2 layers of 2oz or a layer of 4oz S glass instead.   Another alternative may include adding high density PU foam for the rails.  

The questions I have are as follows:  has anyone here tried a thin+veneer combo like this, and if so did you get any flex out of it?  Secondly, how much extra exposure would I be getting to the board snapping in half?    Besides that, any suggestions (like - waste of time, or don’t do it) or alternatives?