I guess a lot of how to solve this problem depends on use -- how much actual damage you expect to suffer and how important it is to you to be able to repair damage when it's done to the protective stuff. The smart thing about wainscoting (had to look up how to spell that) is that it's often made out of multiple pieces -- which makes me think replacing individual pieces without having to tear the whole thing out was part of the plan. A lot of time it's also hardwood, which is tougher than plaster, but the common use of tongue-and-groove vertical slats makes me think (again) of ease of replacement for a section versus the whole.
The thing that bugs me about corrugated metal is that it dents easily and there's no simple way to repair those dents. But I suppose if you installed it vertically, with a cap piece that was removable, you could replace individual sections (what is that stuff, 3' wide?). It is pretty inexpensive, if I remember right.
It might be worth looking into inexpensive fencing materials, like pine slats, as a way you could have a protective layer that's also repairable in small sections. Is there any kind of cheap plastic slatting that could be re-purposed for this? Something 1"x.25", even if it was flexible like a Hot Wheels track, could be held in place with grooves above and below and maybe a little adhesive.
Old pallet lumber?
I'll bet someone with some time and a way to trim it out could even make OSB look good, if you paneled it like interior wainscoting.
Or I suppose you could just be really careful with your sheetrock garage walls.
But where's the fun in that?