RockSliders:

 
These are pictures taken during the fabricaiton of my rock sliders. They are 1/4" wall 4x2, welded directly to the frame.
 
Taking some intial measurements:
 

 
Welding on the braces:
 

 
Expanded metal on the top for grip:
 

 
The braces are welded to a 1/4" plate, then welded directly to the frame:
 

 
Final product: