I'll back this up. I have absolutely no complaints about my experience opening my IB Canada account or the service I get. I certainly have more than $5K but have never had 1/4 mil floating around in that account.
I would not suggest the offshore method, that is more risk and the account may not be insured under that jurisdiction. If you want to minimize taxes then you need to form a trust, for that you need expert help. not this chat forum.
I am not recommending them but you may want to look into disnat direct. Last time I checked there prices were really compitive. They are part of the DesJardins group that is a psuedo co-operative that reflective the distinct culture of Quebec.
Hey Dr. F. What university are you with? Sounds like some very interesting research you are doing. mnx