Just in case you poke out your iPhone's camera with a nail, there is actually an iPhone camera replacement part available.

I am actually not sure who would buy that replacement part. It sells for $29.99 on several stores. Replacement requires some technical skills and if you under warranty you should not open your iPhone anyway.
The iPhone replacement camera part is available from Vavolo. There are many more iPhone replacement parts and tools to tinker with your beloved iPhone.
The We love Macs store has a nice list of available iPhone parts including the iPhone front bezel, iPhone aluminum back panel, iPhone frame, iPhone antenna, and the iPhone click button.