Funkychip,
Yep, it's custom made, by one of my father's part-timer. He was so excited about the design (I usually have weird stuff for him to make!) he had it completed in 6 hours + curing time.
This was actually experimental, trying to good sturdy terrarium without it being too heavy. There's actually a 2" gap on top of the glass chamber, I was thinking of putting some metal grille or if I'm putting it indoor, some lighting. Since I have it outside under the porch & I've put all them highlanders in there, I decided to cover the hole using plain old Gladwrap
I don't have a hygrometer, but based on the amount of condension I see every morning (actually there aren't much to see, it's all fogged up), I'm sure the humidity pretty high. Anyway, lately it's easier to look into the terrarium without opening the door (ususally it's all foggy), and that could only mean the weather is getting very dry!
And I line the base with NZ lfs & top it with live sphagnum moss. It works miracle!