Thats a pile of tough suggestions.
If you stock high end rifles built by a reputable builder, your problem will likely be why would someone pay the price for a custom gun if they dont get to spec it the way they want (unless they are happy with the existing build specs). When you get into that end people want certain chamber specs for certain bullets/brass, barrel length/contour, etc etc.
Any of the quality high end tactical bolt guns have Canadian dealers/distributors (AI, SAKO, DSR, etc etc).
Selling your lower end off the rack remy, savage, win etc is just like someone in a previous post said, you up against the big box stores.
There are dealers who carry borden, dakota, and so on. Ask them how many they bring in and sell. I wouldn't think that number is very high, nor would it be much higher if you acutally had the $6k + rifle sitting on hand waiting for them to buy it.
I think thats a tough subject to ponder. You don't want something your going to stock and make little to no profit on, yet it should be something middle of the road that the average Joe looking for something better than your off the shelfer Remy could get into.
(When you find that let me know, I'll partner up with you)!!
Take care with your venture,