Have a look at the PipeWorks demo. There is a module that create and declare its own unique ID each time it is constructed. There is no Flex dependence in this class, even if the demo is for Flex.
http://puremvc.org/pages/demos/AS3/Demo_AS3_MultiCore_Flex_PipeWorks/srcview/source/org/puremvc/as3/multicore/demos/flex/pipeworks/modules/PrattlerModule.as.html