[LocoJason]

In looking at this for a moment, I felt I had a couple things to add. Due to wanting to keep my job, I can't give any data. I can give you some information to fuel the discussion.
-There are many reasons for hanging the throttle open at speed, even when the pedal is at zero. The biggest one is emissions, as was already pointed out. Keeping the cat "lit" requires both AIR and a little fuel. But also, this function also enhances the drivability by decreasing (or making more linar) effect of the varying deceleration rates of engine braking at different engine/vehicle speeds. Both the inputs and controls for this sort of feature vary widely.
-I can't give a "1RPM" discussion any consideration because there is no gasoline engine I know of in existence that runs this slow. When people say the load is more important than the speed, that's very true but only part of the story. At low engine speeds, port velocity and mixture motion is very low, so charge stratification (fuel/air separation) is rather high. This leads to needing more fuel at lower engine speeds in order to maintain stable combustion (Low CoV). The gradient varies greatly form engine to engine, but suffice it to say that with all other values being equal, there is a non-linear correlation between engine speed and fueling.