I've also thought of testing a related idea, of using a pair of throttle bodies in a staged configuration. The primary throttle body would open first, and would have a rather small bore diameter. The secondary throttle body would start to open once the primary opened fully, would have a larger bore diameter, and would provide additional air to the engine as needed.
This idea uses the same principle as the warm air intake that seems to be popular here. Get the throttle plate to open up more, thereby reducing drag loss past the throttle plate, while maintaining the same engine power output. It isn't going to do much to reduce intake vacuum, but it's better than nothing.
Before you write off this idea as being half-baked, consider that the 1989-1992 Ford Probe 2.2L I4 and several Mazda models used this exact configuration in one form or another. Note that in each picture, the primary has a smaller moveable surface area than the secondary. With the Probe throttle body, the secondary consists of a single larger diameter bore. With the Mazda rotary throttle body, you can see that the secondary consists of two more throttle plates.
