I know the scale is drastically different, but I know at Bungie the floor is open and the desks are on wheels to allow the working groups to change as the team works through the requirements -- as another poster mentioned above.

If you were to go for a setup like this, there are some other considerations -- having the tower attached to the desk so that it moves in one piece (I've often wished for a desk with 8-9 Units of space for rackable rigs.), having a power-strip (and possibly local network switch) attached as well to minimize re-cabling (which prevents cable-clutter from forming -- wire it once, wire it right), Ideally moving the desk should be as simple as pulling a single power and network cable (or rather, one network cable for each physically separate domain, should you employ them), rolling it over and jacking back in.

Also, you might consider locating some of the staff in the other space... It doesn't seem like you'd need that whole space for just the IT back end... I know one of the local places I interviewed at had a server room smaller than that, and they had 3 studios totaling close to 200 people on-site, as well as functioning as the central hub for other studios in the organization located in the western half of North America. These would have to be people who don't need to be in the thick of it all the time -- corp folks & reception, IT folks. May not work in your situation, but food for thought.