 Apple Supplier List – Top 200 [pdf]
There is so much information here. It is interesting to see how these suppliers look like something you'd find on Alibaba. Given how massive these companies must be (despite of how they appear to be), I doubt if they'd answer to low volume inquiries.I found the guys that make Apple's USB cables:
Cheng Uei Precision Industry Co., Ltd. (Foxlink)
http://www.foxlink.com/web/en/portfolio-item/usb-cable/#1474...iPhone boxes!?
Brilliant International Group Ltd
http://www.brilliant-group.com/products_electronic/Sim card trays:
Chengdu Homin Technology Co., Ltd.
http://www.cnhomin.com/Watch/Camera glass:
Biel Crystal Manufactory Ltd
http://www.bielcrystal.com/iPhone Haptics/Speakers module:
AAC Technologies Holdings Inc. 
https://www.aactechnologies.com/index.php?m=content&c=index&...Then you come across something truly extraordinary:
Catcher
http://www.catcher.com.tw/technology.aspxCatcher has a market cap of 7 Billion USD. They own and operate 18,000 CNC machines, the largest fleet of CNC machines in the world. This is probably where iPhone case and Macbook Unibody is manufactured.Edit: I found a video of Catcher: https://www.youtube.com/watch?v=UknhWoL6GWQ
Edit: Tons of information on Catcher