Why not some mechanism that would consist of another
outer variable hull layer that would be hinged at the chines allowing
the keel portion to move downward to increase deadrise. It would have
a flexible stiff plastic piece at the front to keep water out of the
area between the two hulls. Is this simply too complex for too little
benefit?
The semi-rigid inflatable boats have much of the operational pieces you
would need to test out a variable deadrise hull; i.e, a planing hull and the
inflatable bladders on the sides.

You would take a regular boat hull and build on an extended keel. Take your
semi-rigid hull, cut it in half, attach a hinge to the centerline and then
attach that hinge to the extended keel of the test boat.
Then, by changing the pressure on the bladders, the rigid part of the add-on
hull would be forced down into a flatter bottom with less deadrise. The
beauty of the design is that you could change the deadrise for existing
conditions, and the bladders would add an extra amount of cushioning from
wave hits.
You would of course need to experiment with hull and bladder shapes and
sizes, but it might work.

An energy-saving green hull design like this might be elgible for some of
that stimulus money, no?