On the adjustable wrench how about you etch a mm scale with an indicator point on the moveable part.Ideal for measuring nut/opening size. Also, as the moving jaw comes out all the way if you serrate the underside and reverse it becomes a pipe wrench. This is used in Sandvik-Bahco adjustable wrenches.
I like the idea of markings, but what I could use would be the correct size (in sixteenths or metric) of the bolt head, e.g., the 8th and 9th marks would be 1/2" and 9/16" bolt sizes respectively.