Chris,
Sorry, I didn't reply to this sooner - I just happened to look into the post and saw that you were calling on me and Chris Harper in particular. Anyway, I've done a good bit of searching myself on this topic. A few sites to look at for good how-to info are:
Zoopoxy/Polygem epoxies
http://www.polygem.com/zoo/zoopoxy.php
Bob/Odiatriad site regarding faux rock construction with concrete
http://www.treemonitors.com/diyfauxrock.html
Additionally, just doing a Google search for fake rock along with other keywords such as pond, aquarium, fiberglass, concrete, etc. can net you a lot of results.
This site isn't entirely realistic, but you can apply the techniques to a better laid out rock design
http://www.cichlid-forum.com/articles/diy_aquarium_background.php
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Matt Campbell
25 years herp keeping experience
Full-time zookeeper
Personal collection - 21 snakes (9 genera), 20 lizards (4 genera), 6 chelonians (2 genera)