First, $800 CAD is under $650 USD (to put it in a value to which I can relate) and that's barely enough to buy anything remotely decent NEW from a reputable brand. This is a beggars/ choosers kind of situation, so until you can expand that budget, you're left scrounging the bottom of the barrel. I'm not talking down at you, just explaining the way things are.
Chain Reaction and BikesDirect might have something for you but supply chains are all screwed up right now. Keep an eye on those types of discount sites, but be aware that good deals will go fast due to current demand.
I don't know the Toronto area very well but the CL and PB listings for that area are pathetic! That really shocked me. sorry that's so crappy. I have found in recent years that Craigslist is lousy and I have much better luck finding good stuff on the Facebook marketplace. don't have a FB account? that's your choice.
With your budget, if you want a mountain bike, you're going to have to wait, save your $, and jump on the next deal that comes along that is the appropriate size for you. You need to have the humility to accept that your conception of how a mtb should fit is based on nothing, and that the advice of every bike designer with centuries of combined experience behind them would never build a mountain bike to fit a person of your height with the bizarre dimensions that you have in mind. sorry if that sounds harsh, but I don't think I am doing you any favors by sugar-coating the truth for you. it would be a disservice to you to let you continue on this weird fantasy line of thinking about how bikes should fit. there's a degree of variation within each fitting ideal where you can adjust for your individual preferences, but your ideas are something like three standard deviations from the norm. if you can't see past that, you're on your own with weird Frankenbikes, or you need to pay a custom frame fabricator to build something just for you.
Last edited by mack_turtle; 01-25-21 at 08:09 AM.