I converted an old gun cabinet into a humidor. Basically, I just sanded down and restained it, Sealed up the glass in the door and lined it with SC.
Here is empty:
And full(these are several months old, so the collection has kept growing):
I have also switched from KL to HCM beads. The little white boxes in the photos are wireless hygrometers, I keep the receiver on my nightstand. All the dividers are moveable, so I can adjust each shelf accordingly.