MacDonald, Dettwiler and Associates Ltd. is a Canadian company that is trying to get involved with the business of re-fueling satellites. According to the article, they have not quite shored together their business case. They say that there is enough private interest, but not enough government commitment.
Back in 2007 feasibility of this technology was tested by DARPA and Orbital Express. While the mission had some issues, they were able to refuel a satellite successfully.