I have put together a page outlining a proposal for GTA fare integration. This could be extended to cover the entire GTHA as well, but I describe the GTA only to keep it simpler (as well as a shorter page showing what currently exists). Only transit agencies that immediately border on Toronto are included.
This is just an initial draft and will no doubt be revised, partly due to feedback I receive. By all means, look it over and post your comments here.
January 20 addition:
There has been discussions on other websites and in the media (see this article from the Globe and Mail) regarding a Metrolinx report on fare integration that was to be on the agenda of last week’s meeting, but for some reason was quickly removed from the agenda and removed from their website. In case you haven’t seen it, you can take a look here.