Jordan and Slippy
if you are looking for an Image for your background, you might wanna try www.thatpetplace.com they offer a nice selection and have pics of all of them. I have also used styrofoam to shape rocks and siliconed them on the back wall of my aquarium. I coated them in concrete. but I am sure this could be done in a terrarium. I would imagine it would be easier than doing so in the aquarium. you could also shape planters into the styrofoam for the plants you want there. just some ideas. good luck
Bob

You could try attaching cork bark panels using silicone and then filling the space between the cork with Greatstuff expanding foam. I used this as a background in my terrarium and then coated the foam with black aquarium silicone and coco peat to make it look natural. I anchored several pots into place and then filled around them with foam for larger plants and mounted the smaller ones. You can also attach pieces of drift wood into the foam so that the frogs have some perches. This method is very secure because the expanding foam attaches everything together as well as to the glass.

I have an aquarium background on my tank. It's the one with large pieces of wood and some plant that looks like moss and some grassy plants in the back against a black background. The only way you can tell it's an underwater view is the glass shrimp (if you look very closely) and if you really know your water plants. Otherwise I think the cork bark is an excellent idea. You can also buy cork tiles at Home Depot that you could silicone to your tank walls. Just use lots of silicone and even cocopanels would work.

CAMBYSES, could you give me some instructions on how to do the styrofoam/concrete method, and what I would need for it? It sound interesting, and I could even incorporate a waterfall into it (at least I hope so).
Thanks