<would wood work (say that 5 times fast..) on the bottom and 3 sides and plexiglass on the front..? i know humidity would cause the wood to warp over time tho right?...>
absolutely, i think wood is one of the best materials for a terrarium. if your worried about humidity then use MDF, plywood or tempered pressboard(or hardboard, don't remember the exact name but it's pretty strong ime). because they don't have a set grain direction they will resist warping and will expand in several directions equally, basically they're the best for humid setups. another thing you can do is paint the terrarium with a good primer or deck sealant. i like plexiglass because it's so easy to cut, is light weight and isn't so easy to break but it will warp if you don't have it secured on all sides. i'm not sure but it shouldn't warp if you don't have a light over if, you can always try and replace it with glass if it doesn't work(HD has some 1/4" acrylic cheap)