April 2012 Update:
The above steps will only get you the top-left corner coordinates of any given shape…the same coordinates one can get by saving the file out as an SVG. After having done a thorough internet search, I conclude that there is no way (at present) to export the CENTER coordinates of layers from an illustrator file. I may write something myself…or I may just go in and transcribe the coordinates by hand. If I write a script, I’ll post back here.
Happy hunting, internet future-persons.