Are you talking about the kind the has a lip on the lower back side so it will hook over the block below? These are not actually called "paver" I don't believe, but they do build a great wall. Problem with going too high is even if you backfill behind them with gravel as you are supposed to do, eventually there will be a great deal for pressure pushing on the wall. I have a free standing wall 8 blocks high made with them, but it is around the edge of my deck so there is nothing behind exerting outward force. I belive this is a limit to the height of a retaining wall with these type, but I don't recall what it is. The store that sells them should have information on this.