iFixit (http://www.ifixit.com/) has opened and disassembled an iPod Touch.
It seems most of the space is dedicated to battery and screen while the electronics are all crammed in the bottom where the connectors are.
What remains unclear is whether there's the components needed for bluetooth or not.
As all other electronics from Cupertino it is a great work of engineering and design.
You can find all pictures here.