I hope that one of these sites gets developed by the right people and Canada gets it's Sand Hills moment. Sooner rather than later.
I'd say the chances of a Sand Hills location in Southern Ontario are zero due to severe government restrictions. I've searched almost the entire southern part of the province for a sand hills type site and it's like banging your head against the wall every time. It's not to say it will never happen, but I'd be hard pressed to come up with a situation where it could.
In regards to central Canada, it would also be very difficult and the feasibility would be pretty much nonexistent. We found a site in southern Saskatchewan about 10 years ago 1.5 hours from a somewhat major city that is spectacular, but again, the viability of such a location was and continues to not be strong enough unless someone wants to go in there and just create there own private playground.