I have just checked in the flex-utilities/FXGTools project which supports the following:
a) Converting an FXG file containing a Library of symbols (created in Adobe Illustrator) into individual FXG files b) Optimize i.e. clean up the FXG generated by tools like AI, Photoshop, etc. by removing the unnecessary Group nodes. My plan is to keep adding more functionalities to this tool and hopefully write a plugin for Illustrator, Fireworks, Photoshop, etc. The UI is very barebones but that will change soon. The 'optimized' portion of the tool can be used on our FXG skins that ship with the Flex sdk. There were concerns about the performance implications of the unnecessary group elements created by the image editing tools. Feedback and requests for features would be wonderful. Thanks, Om