I think you are limiting yourself to metalic conductors and semiconductors. The protons at cern, do move and fast. In solutions the current may be carried by ions, and the predominate ones may not be negative.But protons don't move (other than brownian motion), the positive charge is the absence of the electron that has moved on. Unless we are talking antimatter or some other exotic situation, only the electrons move. Holes are just a concept that makes the math easier.
Arguing that current flows in the direction that electrons would flow if the are the only chage carrieries is not too different from arguing that since electrons are the most common charge carrieries they should be defined as positive, not negative. Direction of current flow is a convention, and confusion comes from messing with it. If you want to try to change a convention that makes even less sense then lets get after the qwerty keyboard.
I hope no one take offense, this is sort of fun to argue about, and I like to be on the correct side, but mostly this is not an important issue.
Keep in mind that x is horizontal, and y is verticle (sp ) and if you mess with it too much the cross product reverses direction.