Developers for the most part don't care about an arbitrary number like 1000ft. It's more profitable for them to build lower than that.
Is it out of the question then that Toronto could see a tower in the ultra tall category? Could you see that happening in the next ten years under any circumstances? The city is becoming very tall - which I love - and a brilliant hub for many activities including financial industries, education, medicine, research. Is the city 'big enough' to attract development like this?