Turning Dresser Cabinet into Humidor

I like the idea of the Spanish Cedar box to slide inside of the cabinet, where can you buy wood like that to create the box? I'm also still on the fence about what type of humidification device to put inside... would beads suffice? or should I get some sort of electric device? Any links to stuff?

What about something like this? http://www.ebay.com/itm/140552055810...84.m1423.l2649