In yesterday's Metro (link PDF), there was an article ("Regions vie for TTC cash") that talked about a possible "Lakefront LRT" project:
I've had this project in my mind since the Harbourfront Streetcar was extended to Exhibition Place. An extension of this line from the The Ex to Queen & Roncesvalles is the main work that is required to create a high-speed option for bringing west-enders into Union Station. Streetcars already move in their own right-of-way along the Toronto portion of The Queensway. West of the Humber, both Lakeshore and Queensway are wide enough to consider building LRT lanes.
I have emailed both of the Etobicoke-Lakeshore City Councillors -- Mark Grimes and Peter Milczyn -- but neither has replied to me with any information about the proposal. Based on my own assumptions, I've put together the map below. The extension along Lakeshore West is what is planned; the Queensway extension could be a future option but isn't warranted at this time.
Ed Drass has more about Wednesday's TTC meeting at which these and several other expansion projects may be discussed. Obviously, there is not enough money to go around, and the Scarborough RT replacement is necessary. However, the advantage of LRT developments is that they are relatively cheap compared to subway investments.