Vaja has debuted its first two cases for the iPhone 4. The iVolution Top is a flip-style case with a fold-forward screen cover, a leather exterior, open access to most ports and controls, and embossed interior lining. It is available in a wide range of colors and leathers and sells for $80. The Classic Retro Slim Bag is a sleeve-style case offering a vertical front stripe and opening for the power button for $55. Both of Vaja’s new cases for…