Oh man, I REALLY wanted to make an enclosure with tons of fake rocks, a fale background made of great stuff, silicone, and cocobark, lots of pieces of wood, a water fall and a pond, and live plants galore for some Poison Dart Frogs.
It turned out to be very expensive. I got about half way there, but didn't really have the know how to set everything up. I ran out of money and was kind of intimidated to proceed.
I still have a ton of nice wood pieces from that endeavor though, that I use in my snake's bins. Mine aren't as elaborate as Nanci's, but hers are the model I'm striving after. I pick up fake plants wherever I can, and I always make sure there is enough cover in the tub. We have to consider what corn snakes need though and what we need. We like an aesthetically pleasing enclosure that makes us feel "good" about keeping snakes captive. Really, there's nothing natural about keeping snakes captive anyway, and I've noticed that the hides snakes seem to feel the most comfortable in are the "unsightly" cheap ones anyway.
Also, I'm not sure what the curing time is for silicone, but Don Soderburg warns against it in his book. Because we use heat for our snakes the silicone (or whatever else you're using) heats up as well and is more likely to emit chemicals. He recommends a curing time of at least twice as long as is recommended on the box.