I remember at the 04 surf expo there was a guy at the regal session boat (by the way whatever happened to them?) and he was talking about and aftermarket product similar to the wedge but called... I think it was a "whale tale".
William, it actually works in the exact opposite maner, unless you're talking about trim tabs which are something entirely differnt altogether. A mechanism similar to the malibu wedge would create more of a down force on the stern and would sink the back of the boat, acting like ballast. It would be more difficult to stear/plane but it would change your wake shape and possibly even make it larger.
trim tabs, like those on a tige' do exactly like what you described, by putting them down, it pushes the back of the boat up, making it easier to plane, one you're on plane if you put them up it makes the stern drop deeper into the water to produce a larger wake. If you have an outboard boat or an i/o the trim on you're engine does the exact same thing. I've had a sea ray for a couple years, and had outboard or i/os all my life and when I got into wakeboarding thats what we did, trim it up little by little and you can actually watch the wake change. Anywho, hope that helps. Good luck and have fun!