Geeezzz! From out of the history books, gjm6syn6, brings up a question of making up a rope ladder; and, that's exactly what we used, to drop pits before going into SRT, back in '69. I'm probably not understanding what you're trying to make up, what with "square knots," "clove hitch," "directional eights," and all, but we used to make up rope ladders with oak rungs and five-sixteenths nylon rope like Scott wrote, place them about 12-18" apart. We used a basic figure eight knot, slid the rungs on and moved on to make another figure eight knot, and so forth. It worked fine and dandy; and, when we had deeper pits than 40-feet, we attached another section of ladder to the one we were using, so we'd have 80-feet or a 120-feet, etc. We did use a belay line with a guy staying topside...or if all of us were on a long trip, we'd belay from the bottom, after the belay rope was put into the top run area with a biner.
Now, if we're trying to make up a rope ladder, just using rope, then I see where you might be coming from...and don't believe we would have used such a contraption. Of course, we did a lot of vertical work back then, so making loops and such just didn't appeal to us. As far as Scott's comment that they wouldn't be as good as a cable ladder, I have to disagree, for our rope/oak rung ladder was the cat's meow for the most part. We used the cable ladders after they came out, but never made or purchased any of them, but found the way of climbing with them, a little awkward. Our ladders were 12-14" wide. Can't recall right off hand, but...if someone wants to buy a section, I still have one that's in neat condtion.
The cable ladder is narrow and placing the foot behind the ladder and so forth, just kind of upset folks. I have some pictures that I'll see about posting...and if you want to do a PM, write away!