This Pedal is currently available.
FX Loop / Signal Blender
Features volume bass and treble knobs and a boost switch for +6dB boost.
Xotic X-Blender$227.66
Xotic X-Blender$239
Xotic X-Blender$170.69
Xotic X-Blender$239
Xotic X-Blender$207
These merchants probably sell this module. Huh?
Xotic X-Blender Effects Loop Switcher