Full service as in they sell things like accountability, certification, and someone to point a finger at. Smaller companies don't have the resources to do the things Rackspace can, which is why they are able to price their services so high.
People always forget that big companies do business with big companies so that they have someone big enough to sue if a major deal gets soured. (See BP trying to sue everyone related to the oil rig that started the Gulf spill to get money back)