Alright, well I've implemented everything necessary, including all of the configuration code, for the base SpriteGen to work. So, as soon as I get some ghetto pages together to allow you to upload a zip and process it, I'll let you know via an update here. However, the way the SpriteGen queues work items and notifies you that 'your sprites are ready' will likely be changed, due to the fact that I eventually expect some decent traffic coming through and using it. The packing algorithm is pretty slim and easy, but who knows how hard it would make my web server work with 20 concurrent requests.
Stay tuned for the URL to the SpriteGen.