I cant come up with any move related with rasengan that could be useful so lets see what kakashi is thinking (I hope it isnt some kind of tornado punch like those of Joe Higashi in fatal fury) . Even if its a new jutsu for naruto its a bit lame having another person telling you how to create it and train you to do it.

Some one asked for the akatsukis former villages.

Hidan - Rain village

Kakuzuu - Waterfall village

If I remember well the waterfall village appeared in one jump festa (that one with the hero water) and it was a crappy village with very few weak ninjas and without hokage. Maybe that was "another" waterfall village or just a filler plot mistake.