Cressy has said that they are keeping the location secret because
they haven't yet approached the property owner. So if it is 101 Spadina, not even the owner knows yet.
I can't think of any other obvious locations that don't involve tearing down an existing tall building, many of which are protected for their warehouse character that the city wants to preserve in the area.
The parking lot around Quantum Coffee is owned by Allied but is classified as future development with no imminent sales or even any project details. It's a candidate but the park would be fairly small and narrow, although it would be nice surrounding the restored Tudor building and brick warehouse, with a patio facing into the park.
@smably suggested MTC but that land and the Shoppers Drugmart are an active project in development. The lot behind it has also already been built on and that would limit the size of the park.
The LCBO is also an active condo project which the city has been taking a role in ushering into a pedestrian friendly realm.
The cluster of low rise buildings on Spadina at Richmond are a possibility but this is no longer King West. It's Queen St at that point and King is the neighbourhood with exploding population.
That all said, the Spadina/Adelaide location also presents an issue where it's very close to Clarence Square and St. Andrew's Playground.
I'm all for new parks but this immediate area is well served. I'd rather see existing parks expanded and redeveloped.
Clarence Square can be expanded into the LCBO project where the pedestrian zones could be merged into the park and St. Andrew's Playground is already being expanded into the parking lot next to it. I think that the real potential lies in David Pecaut Square which can be converted into real grass and the amount of trees can easily be doubled or even tripled.