It doesn't have to be cash - I don't think it's advisable to travel with that kind of cash. It can just be a bank statement showing that you have the equivalent of Can 10K in the bank. They make it this high because it can be quite difficult for some professions to find work in Canada e.g. Engineering. So someone can go for 8 or more months without a job and they would need something to live on. The government doesn't want you applying for welfare or tapping into public funds, so that's why they put this requirement in place. I came here as a landed immigrant 6years ago and even though I had bank statements showing I had the required funds, no-one asked me to provide that proof. When I landed, they only asked to see my immigration papers and nothing else. I doubt there are a lot of people who are asked to show this proof of funds when they land, so I wouldn't worry too much about it if I were you. Since you are planning to settle in Ontario, have a look at the following website - it's an excellent resource for people planning to settle in Ontario:
http://www.settlement.org/