OP:
I was thinking on your boat need today while freezing in a deer stand and I might have missed the obvious. You want stability and economy. Take a look at the Puddle Duck Racers/PDRs. There is lots of info out there and many have been built. They are a far better choice then the Hybrid boats. If you research them you will see the ones with low sides perfect for a sneak boat. They are originally designed to be economy sail boats but they will row pretty good. If you built the basic hull with out the air boxes you'd have a very vesatile and rock solid stable base to shoot from, build a blind on etc.
-Far easier to build, they are designed for wood chines.
-Cheaper to build
-more stable
-Easier to row both because they are wider and because they have rocker/curve to the bottom.
-more stowage space
Below are some pics from the web that might give you some idea of the versatility. For a true duck boat keep in mind that at reasonable wieght she does not put much if any of her transom in the water, that means huge savings in sweat to the oar operator compared to the hybrid and it also means you can shorten the sides alot.
here is one with the sides lowered, imagine it with no sail and flat, ducks would land right in it!
basic hull with 16 inch sides and part deck
If you wanted it partly decked (can't see why but....)
Endless possibilities
Plans are free takes 2 sheets of 1/4 inch ply wood, a 1x10, some tightbond III glue, few nails and hand saw to build