pretty much, which volume pedals can be set so that all the way back=no sound change and pushing it forwards increases the volume to a set amount?
i dont think i have seen one that can do thi. but you can take a small block of wood, or some guitar picks taped together if you're zakk wylde, to put under the heel side of the pedal. this way "all the way down" is now only as far down as you let it go. then all the way up is just all the way up.
I could be wrong, but I think the Visual Volume can do that.