TC has now developed a lower link skid for the 4Runner and FJC.
The new link skid is more compact then some out there, but seems to do a good job offering the protection where the protection needs to be. I've compared a few, and liked their thought process here.
This is what Total Chaos has to say...
Lower Link Skids - 07+ FJ & 03+ 4Runner
Protect your factory FJ & 4Runner lower link brackets from rock damage by installing these TOTAL CHAOS bolt on lower link skid plates. Designed using 3/16” mild steel, these brackets bolt on using 9/16” grade 8 hardware. They are designed to work with factory lower control arm links and aftermarket upgrades. TC link skids are intended to bolt on but can also be welded to maximize the reinforcement to the factory bracket. They incorporate an added spacer that is designed to prevent the factory tabs from elongating like the other brands. The TC skids were designed to reinforce the gap created from the taper design in the factory bracket.
Here is a shot of TC's new Lower Link Skids on my 4th Gen 4Ruuner. Mine have the forward facing tab welded to add strength and to eliminate the chance that it could get caught on an obstacle.