Security :: User Access Restrictions To Network, USB Ports, PCMCIA, CDROM

How to create a user account on a Linux desktop machine with restrictions on connecting to the LAN, WAN, PCMCIA ports, Firewire, CDROM and generally any user controllable output options?

I have the task to set up a machine for users working with sensitive data that should not be leaving the machine where it is processed. This means disabling access to the ethernet device, lan, all other ports as mentioned earlier, and any other way of leaking the data.

In Mac OSX this was achieved using "Parental controls" from the System preferences; this even allows a selection of the applications that can be used. Under XP, Device Manager offers the option to click various devices and "Disable" them, which worked so far just fine. Some will point out that the latter mentioned OS may be easy to circumvent the security of in other ways, but that has been mitigated with other measures and it's not the point anyway. For the operator users in question, the aforementioned measure proved successful and worked.Using OSX and XP to do this was a 10-15 minutes job with testing included.

So far all guides and tutorials pointed to useradd, groups an facl, but in actual practical terms did not help at all, in fact most of the research did not render any practical results so far. I surely don't expect to point and click, and would gladly run a set of commands from CLI. If I had them. I would really would like to achieve the same restricted user account configuration in a concise, comprehensive and practical manner under Linux too. Preferably tested on humans before, and known to be workign, of course.
The machines that need to be set up are two laptops running Ubuntu. So how can this be accomplished in Linux?