Having looked at almost all of the plugins listed, it appears that the payware ones -- with one exception -- are multiband processors rather than splitters. In other words, they are stereo-in-to-stereo-out (or mono-in-to-mono-out, etc.). I'm looking for some with four (or more) pairs of outputs. The exception is HoRNet 3XOver, which is a two-way crossover (3 bands).
So far, the only thing I've found that is a 64-bit VST with four or more bands is Blue Cat MB-7 mixer.