Yes, most of these are, indeed, under the large LSI chips and near the CPU. Propagation delay matching is probably the best reason I can see for this rather artful artwork. I guess at approaching 800 mHz or more it does become very important to keep all the bus lines at the same length.
They very much reminded of queing lines at amusement parks for the very popular roller coasters, like The Beast at Kings Island. First there's a straight line followed by what I call the "cattle pens" where the line just zig zags. This repeats 5 times before you get a glorious 2 minutes of exquisite terror.