The 10 dollar trays from cheap humidors are little tray's one per self but they waste a lot of room, too big to put two on a self, the ones I bought aren't really "shelves" they are just cedar trays / boxes.
You should be able to find the dimensions on the site...
http://www.air-n-water.com/newair-wi...FceDQgodWDYA0A
Old picture when I used them, they look a bit bigger than they are here but you can see the wasted space.
Then when you are ready there is always...
http://wineadors.com/