[R]esearchers have shown the Leidenfrost effect works very well in reverse. They dropped metal balls heated to different temperatures into a liquid and watched how fast they fell. The chose a room temperature ball, a heated ball that wasn’t enough to make the Leidenfrost effect occur, and a ball heated above the Leidenfrost temperature.
Moving through water vapor is easier than through liquid. There should be some speed where you can’t boil the water quickly enough, though, and you get a transition of the effect in the right-hand tube to that of the middle tube, or something similar.
That is for free fall. We wonder about projectiles moving rapidly, say local 0.6 speed of sound and 1.2 speed of sound.
There’s more than one way to create a vapor layer for less drag in a fluid
http://en.wikipedia.org/wiki/Supercavitating