Chinese iPhone parts sites start to list the iPhone 5 home button. The iPhone 5 home button looks slightly different.
A Chinese parts site called TVC-Mall has started to list iPhone 5 home button replacements. If legit the new iPhone 5 has a rounded square shape. If this is the actual part it would mean that the iPhone 5 has no advanced tiny home touchpad and also the idea of Apple dropping the hardware home button would not come true.