Well, you really are a Dot Com God! lol Congrats! Can I buy and sell .ca even though I am not located there? The way I read it is that I can't.
Do not take this as legal advice.
You would need to set up a corporation in a Canadian province, possibly as a subsidiary of a corporation you may have formed in the US, depending on the province's citizenship/residency requirements.
This corporation would then become an "eligible entity" under which you could own and in turn, buy and sell .ca domain names with.
However, as the domains would belong to the corporation, so would any proceeds realized as a result of selling/parking/developing them. Therefore they would not be "yours", per se. For you to enjoy the profits, the money would need to be removed from the corporation in methods to include but not be limited to a loan, a dividend payment, a salary, or a "commission" to you as an independent contractor of the corporation (which I have done in the past).
If you were to opt for the latter, you would have to pay tax personally on your commission, and the corporation would have to pay tax on the net profit resulting from the domain's sale.
Getting this set up is not a cheap undertaking, so you should have realistic plans to make the operating expenses back before you go ahead with this.
If it's just one or two names you're going for, this all probably isn't worth it, and I'm sure that you know somebody who would fall under the category of an "eligible entity" who could be a front for the registration for you.