We certainly could have a made-in-Canada system, by all means. The distinction to remember is that any single-member district system will necessarily be a first past the post system, so it would not be proportional. You could have single-member districts as well as multi-member districts, just recognizing that the only proportionality would come from multi-member districts. The extent to which that is going to be liked across the country is something to consider.
Certainly, geography is a challenge in these issues. It is made to work in other systems. There is no perfect way of looking at it. You could do a mix of first past the post and PR, but it might raise some other issues. To be fair, I have never seen that anywhere else.