the problem with this is that IMO "Users" are a lot more Savvy than typical I.T support guys in most big organisations.
For example the I.T computer support guys might be earning around 10 - 15 EUR an hour and are often experienced in hardware etc but can't really compete with other types of professionals - often highly skilled graduates earning 60 - 200 EUR an hour.
So Option 4 is not really a good idea -- sharing data across a LAN is a HIGH risk of Data compromise. Secure data should be SECURE and NOT be available via a LAN.
Even in my own case - I needed to share a file with a colleague who was in another building - and we wanted to bypass the email system (not because of a virus - but because the email system had a 5 MB attachment limit) --I could have "rar'ed" the file and sent it in a few chunks but couldn't be bothered.
So all I had to do was to enable "Share " on my DVD device and allow my colleague to access it on his workstation --it's all possible on a local LAN.
The I.T support guys swore blue in the face that "This was not possible " -- but there's none so blind as those that don't want to see" as the expression goes.
Most I.T support guys do a decent job and work hard - but sometimes they aren't as experienced as the guys working on the gear they are supposed to maintain.