I generally agree with pauldub above...it's much better to avoid blowouts than to spend too much time and money (and added weight) to make the RV blowout proof.
My '98 Coachmen does have some sheet metal liners in the wheel wells to partly protect wires and the air lines and such. I think they are more for protection from stones and such that may be kicked up than from blowouts.
You could probably route the lines through a pipe of some sort. Something like black iron pipe might even be strong enough for a blowout. I suspect many lighter types of pipe would not help much for that. (Avoid PVC if you mught travel in cold weather; particularly when cold, it can break by shattering into a bunch of sharp shards.)
