Hoi, I asked Michael Everson if he had more information about the new symbol for the rupee. He did and I blogged about it based on his information. Obviously this is a special case but essentially when there is a need for new characters there is a procedure for getting them included in Unicode. Once they are in Unicode, fonts have to support the new characters. Thanks, GerardM
http://ultimategerardm.blogspot.com/2010/07/indian-rupee.html