Finite Element Analysis. Maybe. In theory. There are lots of very large square matrices used in the various problems solved by the method. The limit of the technique is generally computing time, although last I worked in the field (about 10 years ago), we were using way, way smaller matrices than are being discussed here, and I don't recall how often the limiting factor was multiplying two of them together. (The usual case is a simple {x} = [M] * {v}).

But I always wondered what FEA would look like if we removed the constraint of model size and computing power.