I am in the process of looking for a boat as well and I have spoke to a couple of dealers and it`s sounded like they do a lot of business with canucks and they will have all the necessary papers in order to get you back home without issue,the big deal of course is warranty if you need warranty work done you have to make the drive again. If your buying used then warranty is not an issue.
In my research there does not seem to be a big price difference in the lower end of the market(10-13K) unless your willing to do all that running around to save grand, as you move up in price a bit there seems to be more savings to be had.
I think the big advantage with buying in the States is the variety seems to be a lot more to choose from down there and the dealers actually have some inventory or they can get it fast unlike our dealers who have little inventory and a 2 month delivery.
I am amazed at the number of used boats that are for sale up here that come from the States, dealers and private re-sellers are snapping these up that is probably one reason that you really have to look hard to find a good uded deal.
Up here the real good deals go fast it`s almost like you have to be driving around with a pocket full money and your laptop searching for a boat, I lost out on a good one this morning.
Snooze you lose!!
Good luck in your search.