I really love the iOS 7 PSD by @Teehan+Lax , but I'm an Illustrator fan for UI. Got inspired to make an AI version, based off of Teehan+Lax's PSD version!
If you prefer psd, go here: http://www.teehanlax.com/tools/ios7/
**Safari doesn't download AI files. Try Chrome if it's not working!