Oh, I have seen that before. Nice job! On mine, I got 1 inch tall by 1/4 inch thick bar between the legs, the rail I added to make it span A to C pillar is 1x 3/8 bar. I got 15 bolts per side, with seam sandwiched between the aforementioned rails and 1/4 inch thick plates on the inside. With four four inch wide legs, plus two end pieces welded to the 2x4 main rock guard the pinch seam rail is very secured against horizontal movement, and for vertical movememt, well it is 1 inch thick steel in that direction. For the assembly to pushed in from the side, the frame stiffener and frame would need to giveway and it is stout with four legs. as for the assembly being pushed up relative to the rocker panel, that 1 inch thick of pinch seam rail will have to bend, keep in mind it is attached by welding in six locations along the length of the entire rock rail, four large legs and two 1x1 inch spacers..
plus the legs have gussets to the feet. after bolting the feet to the jeep frame (stiffened frame) but before connecting to the pinch seam, the rockrail assembly was stiff enough for me to jump on with hardly any movement. once pinch seam connected, it became one with the jeep, and more than in only the metaphysical sense.
I think it is more than strong enough, but your idea is good, like four legs is probably over kill. But overkill is fun, so long it dont weigh too much.
I think we both made much stronger rockrails than many of the ones sold. Some are sold with only six holes for pinchseam bolts, little backing plates for said bolts, that is the weak link in many of the commercially available rockrails in my opinion in addition to only two legs, or pinch seam rails that are far shorter than the pinch seam length.
my buddy installed a rockrail, using the six bolts on the commercially available rockrails. he laid it fairly gently on a rock when wheeling and it folded like a cheap suit at the pinch seam connection., dented his rocker panel. This was at the rear end of the rockrail, near rear tire opening.
I urge folks to install more bolts and use full length backing plates ( with gaps in plate for drain holes of course) I think that is oft overlooked
that ,makes the difference between a rockrail, and a running board. one is simply a step, the other is armor!