A second suggestion of the First Watt B4 (designed and built by Nelson Pass). The factory-built edition is no longer in production, and used examples rarely come up for sale, so be prepared to wait. A kit version is about to be made available, I believe.
The B4 is a discrete design, no opamps, no ic’s. It listed for $1500, sold for about $1200. Really versatile: two channels of 1st/2nd/3rd/4th-order high and low-pass filters in 25Hz increments from 25Hz to 6375Hz, level controls for either the high-pass or the low-pass outputs, switchable.