As you note, the aluminium tube is extruded. Most likely, the small holes along with the large hole for the firewire port is cold punched.
My guess is that the large hole is punched and then that is used as a key to stop the tube from moving while the smaller holes are punched as lines of holes in a radial sequence.
The newest MacAddict issue opens the new iMac and shows the iSight. It's obviously a lot smaller and it seems to be of a different form. I do know for a fact that it's USB, rather than FireWire.
I have a vague feeling that they will slowly start doing away with firewire on consumer related stuff (ipods, isight and what is next?). Just hope those rumors that consumer macs will not contain firewire are false. it is should cost them less than a few bucks to put in a firewire controller but USB controller is virtually free with intel chipsets!