Judy - What a great idea! Have you ever tried using 3 or 4 smaller (say 2" clay pots) using your 'moss in a pot' technique? That way the pots could actually fit under the brims of the larger pots and in theory not take up any extra space?
If tapered pots are used and the bottom is slimmer then the top it leaves a little space between pots. Do you think smaller pots will have the same additive effect? I will get around to experimenting when I can get out and find some small clay pots and let everyone know. It sound must easier and neater then pebble trays!
DDS2007 - there is a good section on huimidity that answers a lot of questions. Check it out!
Indoor orchid care in desert (Phoenix, AZ)