I know, I've just moved and am in a rental home. Itll be a couple of years before we buy (just to make sure I dont move again), so Im gonna hold off on rears. Might as well get the fronts and center upgraded.
I'm in a rental house as well. The rears hung with 2 wall anchors, and I just live with the cords hanging down. I tend to agree that you have nothing really wrong with those Polks. I think you will be happier going with the rears. At worst, you can set them on shelves or furniture.
I've been getting around to posting some pictures of my setup and I'll try again tonight.