The JSF is not supposed to have a droid body, the "real" one doesn't have one either. R4G9 is just a head, i believe the same goes for the v-wing, if i interpret this image correctly.
http://www.starwars-tw.com/story/character...-wing-pilot.jpg
so technically only anakin's jsf is "missing" a droid body. then again i have never understood how R2 is suppost to fit in the movie JSF without sticking his feet out of the bottom .