Apple could easily bring in an iPad Mini/Nano between the iPod and existing iPad 3rd Gen, they just need to drop the iPad 2.
Then the product line would be as follows FROM MARCH 2013
iPod Shuffle $49
iPod Nano $149
iPod Touch (4th Gen) 16GB $199 / 32GB $249
iPod Touch (5th Gen) 16GB $299 / 32GB $399
iPad Mini 16GB $399 - Justify price by using retina display resolution 2048x1536 326ppi. A5X chip
iPad (retina) 16GB $499 / 32GB $599 / 64GB $699 A6 chip