Check out John's sticky in the vivarium forum about a http://www.frogforum.net/vivarium-te...struction.html. It includes pictures of an expanding foam background construction. Or google "greatstuff vivarium background" and you'll get a pile of examples, instructions and videos.
Plant stuff often gets asked in the vivarium forum. A plant sub-forum under vivariums might be useful, but the vivarium forum doesn't really move super fast as it is.
Instead of dividing things up into more overlapping forums, I'd rather see more quality Do It Yourself/Plant/etc articles. This has the advantage of information that gets frequently referenced being readily available. For example Don's http://www.frogforum.net/vivarium-te...se-bottom.html should be under Frog Forum - Vivarium Articles but doesn't appear to have made it (I suspect due to time constraints then being forgotten about). And yes, I realize that if I'm going to suggest things like this I should be prepared to contribute instead of meekly staring at my feet like I'm currently doing.