New leaked parts for the next gen iPhone (maybe iPhone 5s or iPhone 6) suggest that the future iPhone might have color options. According to the pictures from BGR, the SIM card holder has different colors and the internal of the iPhone is different from current iPhone 5.
Nothing is confirmed as of now. However, based on other leaks, the new iPhone might get a better processor, camera, battery and it might have its internal component re-designed/re-arranged (based on the design of these leaked parts).
If you want, you can take a look at these leaked parts from BGR.