A leaked version of the iPhone 5 home screen button has recently appeared online. While, it does not look much different from the current home button on the iPhone 4S, it appears to be a rounded-square instead of a circle (details matter if you are Apple). The authenticity of the button cannot be compared as of now, but you can always get one from True Supplier to test for yourself.
These buttons are available in black and white as well. These can be purchased via the TVC-Mall Chinese website.