Um... It's interesting you state the bandwith problems. We upgraded our network infrustructure to 100baseT Switches, the details are unknown to me as I no longer have prevy to the information, I know that we run a microwave link between each location with a fair bit of of bandwith so that is not the issue.
I think they are certainly paranoid about the security.
Currently no video conferencing is done from outside the work place in nor in to the outside world. It's frustrating when there is not enough information in regards to it. What they are afraid is the ability to do something with SIP and RTP protocols. I'm trying to find out more information but I'm cluting at so many little straws that there isn't enough to make a big one.
From the IT but has been paraphrased for liablity
...I got a feeling enabling it for the entire workplace would open the organisation to potential attacks from some crafted SIP or H.323 packets
Looking at some desktop solutions for the internal network to achieve full frame rate etc... Polycom PVX looks decent though haven't had time to go further and see what it can really do as we currently go the Polycom VSX 7000 sitting in a location collecting dust.