There are 5 known elements (Earth, Fire, Water, Lightning, and Wind) and apparently a 6th one now, since they didn't mention the "6th" element in Kakashi and Yamato's lecture Im thinking there are special requirements for the 6th chakra like combining all the first 5 to make a 6th one. So if you can never have all 5 chakra's then the most you could have is 4 right (only 5 since the 6th one would require something special to make it like the rinnegan)? I don't think I have seen Kakashi do a wind natured jutsu yet though (I can only remember 4 of them like Gyoukaku, Raikiri, Suiryudan, and I forget the name of the earth beheading move).
And is the village Pain's in (Amagakure?) a lightning country village? I would have thought that they were more water country-ish.