1995 Defender 110 in Whangarei, New Zealand
1995 Defender 130 in Mooloolaba, Australia
2002 H1 Phoenix, Arizona
On the bridging comment, my father built the ramps of his trailer out of 2" angle iron (pretty much the same configuration you have, maybe the rungs are closer together). About 3~4ft long and about a foot wide. Never bent, flexed, whatever. Even when with an Oliver Diesel tractor on it (dunno how much that thing weighs, but I know it isn't made out of plastic!). If they are good for trailer ramps, probably not that far off from being a decent bridging ladder.
I've been tossing around the idea of making some angle iron sand ladders like the ones described in this thread. My thoughts were to use (test) 1 1/2" steel angle iron. I would measure my tire contact length at offroad PSI and then space the rungs at 2/3 the measurement of the tire's contact length. Overall length wouldn't be more than about 2ft. I may go nearly as wide as my roof rack and have two ladders. This is an untested assumption, but my experience is that 1 1/2" steel is robust enough to use for occasional bridging purposes, yet still light enough and easy enough to handle for sand extractions.
That's a lot of calculating for a pice of metal you stick in the earth and run over with your truck. :P
You know it'd look cool on your 4runner cruising around Denton...