I noticed that PiFBA might have figured out some way to get it done, but the program might need to be altered to create a gamelist.xml file for EmulationStation:
http://code.google.com/p/pifba/source/browse/FBAcapex_src/gamelist.txt
http://code.google.com/p/pifba/source/browse/FBAcapex_src/gamelist.py
