Jacob Mathis, the bassist the of Philly-based alt-rock band The Stone Eye, uses a fully custom point-to-point Wailbone Black Sheep distortion modified for extra low-end gain. You can hear this pedal in action on the single below:
https://open.spotify.com/track/2s2s4Ht2sghxRx6vf6u5zi?si=bfc44626308c42fd