Have you looked at the OACS 5.0 (what we earlier called 4.7, I should post our current view of the numbering system when I get a chance, we discussed it at Copenhagen) stuff closely?
There seems to be a lot of overlap but not full overlap. In particular our current effort doesn't include custom language templates and that may be something we want to merge in.
Also OACS 5.0 doesn't provide "smart URLs". However I've done this for Greenpeace so might want to compare your implementation with mine. The Greenpeace solution includes admin UI to allow a regional organization to define which languages are legal for each subsite, and the request processor only allows these defined mappings (using cached data so there's no db lookup involved.) So it might be a bit more complete than your implementation which, from your description, is oriented more towards implementing one scheme for the entire site without consideration of subsite specific needs. Am I right?
This looks like interesting work, yes. Hopefully we can all coordinate as the OACS 5.0 effort ramps up over the next few weeks.
