If your going to switch sides, I feel there is a much better way than shown on the Red truck. Although, I'm not generally a fan of cutting a frame, it is a better way to go in this case. Look how far in the springs are for no reason...this can be eliminated by making 4 notches on the bottom lip of the frame where the hangers go. No need for any plates (or really any welding), no need to even drill a hole...just carefully cut the lip contoured around the shape of the hanger until it sits flat on the inside of the frame...use the same holes to bolt them back on & weld the lip to the flat areas of the hanger making it stronger than they were originally.
This keeps the springs outboard (about 6" total) more for better stability, leaves you more room for the shocks (also out farther) & more room for mufflers, fuel cell, ect.
I'd assume to get "the right look", your going to be doing a flip & frame notch anyway...so 4 more little chuncks cut won't hurt. Lorne