For those who are wondering what next on the iPhone front, here is a bait to chew upon till the Mac World Expo reveals all. A concept picture of an iPhone Nano has sparked rumors that suggest a three-quarter-size version of phone! Although the renders may look believable, it's hard to fathom why would Apple do such a thing. The iPhone is going great guns, the 3G was needed and they added it. A slimmer, smaller version sounds impractical for this almost-perfect phone. Unless they take inspiration from this Chinese rip-off, iPhone Mini…