In general the music listening market has very little use/desire for more than 10 bands of EQ, so I would guess that you'll have trouble finding something with significantly more bands (say above 20 sliders/bands). Most EQs with 20 or more bands are aimed at audio mastering, which is (for the sake of keeping this conversation simple and on point) part of the music recording process.
So what you probably want to look for is a mastering/recording high-band EQ, or a parametric EQ (sort of like an infinite band EQ) that you can hook to your audio output (similar to how the SRS plugini that's on the JRiver plugin page). Companies that make VST plugins might be a place to start looking.
Sorry I couldn't be of any more help, but I'm like the majority of people when it comes to my media players. I like to set my EQ to how I generally like it and forget about it. Anything more accurate than a 10-band EQ and there's not much point unless you're adjusting it for every new song or album that comes on. I suppose that could be exactly what you're doing, especially if you're DJing or something. Anyway, I'm rambling now...
-JB