Answer to: Why is my Flash LED lit and not turning off?This is a hardware fault. You should take your iPhone to an Apple Store for diagnosis and replacement.
Answer to: about front glass of 4GThe glass is married to the LCD screen with permanent adhesive. You will need to replace the entire front panel.
Answer to: iPhone 4 with bumper and dockYou can buy an Apple Universal Dock and the iPhone 4 plus bumper fits into it with no Dock Adapter present. I can't speak to how that will wear on the Universal Dock, however, as I don't think they are really designed to be used without the Adapters.