As it is a global day, to get beyond just V for Vendetta masks one idea for 5th November is to link it to a colour white, as a uniting emblem eg the suggestion for white as a global symbol of peace anti-war. Turkish solidarity protests recently used white and of course it is good for anti-war / imperialism.
White armbands could become a potent symbol of the movement - see eg
Two thousand years ago, a Roman Senator suggested that all slaves wear white armbands to better identify them.
"No," said a wiser Senator. "If they see how many of them there are, they may revolt."
See also http://www.whiteflag.info which is a web-site written by a member of the Spanish indignados
Also white is the symbol of the Nigerian people's movement against Shell and other corporates plundering in the Niger Delta and also it signifies the Russian democracy movement.