No trick to this at all. On Everest and other locales where long routes have to be laid out over crevices, or even for short stretches on places such as Mount Rainier, mountaineers simply use aluminum extension ladders. They’re strong, fairly light, not too expensive, and are flexible in the sense that they can be used to bridge crevices or ascend ice cliffs. With a little extra engineering, all sorts of things can be done with them. Lash two together for an extra-long bridge or ladder, for instance. When spanning wide chasms, you could use one as a support girder for a second ladder.
No real need to look hard for a photo, either. Look through any book that shows pictures of climbers on Everest, most typically, and you’ll find lots of photos of climbers traversing ladders on the infamous Khumbu Icefall. Of course, one thing I can’t help you with is the engineering science to support what you see happening in the picture. When you take a ladder designed for vertical use and lay it out horizontally, heaven聴or a good structural engineer聴only knows what’s happening to the force vectors and safety margin. I can’t recall ever reading about a case where one of these site-built “bridges” buckled and took its hapless passenger with it into the icy depths (granted, you should be roped up when traversing these things).
So, it’s off to the hardware store for you. Probably 16-footers will be the most maneuverable, yet give you enough reach.