Yes, there are many examples.

There are several people who are Terragen masters and who are also extremly helpful in the official planetside forums. It's really worth not only checking out the images below but also their galleries:

Scene from Martin's gallery:

http://tangled-universe.deviantart.com/art/Strata-Rock-Wall-152572301

Scene from Frank's gallery:

http://nwda.deviantart.com/art/Rock-wall-22b-153286594

My personal favorite from Ryan's gallery:

http://www.archer-designs.com/zp/index.php?album=digital-art%2Fterragen-2&image=climbing-the-chimney-v3.jpg

Some more:

http://www.planetside.co.uk/gallery/f/tg2/7-canyon16.jpg.html
http://www.planetside.co.uk/gallery/f/tg2/file_1367648.jpg.html

One of TG's best displacement functions is the so-called "Fake stone" shader. It can create absolutely convincing stones of all kinds that blend seamlessly into the surrounding. It looks more realistic than just painting some stone objects, because those stones are computed together with the terrain's surface and react accordingly to the underlying geometry and surface restrictions. Dave Burdick made a very good stone generator Metanode for Vue (I think it's included in Vue 8 by default now), but it's still nowhere near the Terragen shader. That's a feature that e-on should definitely look into :-)