I know there are several floating around somewhere. I am hopeless when it comes to woodworking so I wouldn't
even try it myself
The main important thing is sealing the wood to protect it from moisture.
Here's a link to an awesome viv
that is of some wooden construction:
www.poison-frogs.com, a 2002 website dedicated to rainforest vivaria for dart poison frogs, together with lots of pictures, films and more. How to create the right conditions,like temperature, humidity, ventilation, light and design