Hi there Dallas,
1. Yes, NavCanada will allow very long directs in conjunction with the other controlling sectors and agencies. I've been given directs clear across the continent before even while i wonder whether the issuing controller needs to discuss such a long direct with all the other sectors, or whether they just file a new plan and see what the system says, but either way, it does happen.
2. If it is really uneconomical and you need the direct routings, I would talk to the local FIC. They might be able to throw the routing into the system and see what it gets back or offer alternatives to you. 1-866-992-7433 or if you're at the airport and they're not busy, they might let you up in the cab. They're a great resource which I always felt I under utilized back when I was doing my own planning.