There are a lot of advantages to running the cable the way old Three Speed cables run: to a (movable) stop on the top tube (Sturmey Archer calls these a Fulcrum Clip and Fulcrum Sleeve), then the bare cable runs over a pulley wheel at the top of the seat tube and then down the seat stay to the hub. You can do this on a Nexus 7 or 8 if you have the correct anti-rotation washers. But I have had a hard time finding them.
I think if you use the left washer on the right side and vice-versa you'll end up with the arm pointing up at a 45 degree angle, - if that's what you're looking for.
In my case, the reason I chose an IGH is for winter and in that case it's better to run full cable housing. There are cable guides (as opposed to cable stops) that you can purchase to help with the cable run.