We had a discussion earlier on holders i mentioned i would try one of these to store my slabs rather than use cardboard box, so i finally purchased the one that hold 10 slabs (price seems to be nearly the same for 10 and 20 slab). Few sellers currently sell this product online (amazon, ebay etc).
The build seems pretty solid but the glass lid does seem like fingerprint/dust magnet. The PCGS slab i had in reach seem to fit in quite smoothly but doesn't seem rattle around in the holder. It is little expensive around 20 bucks for 10 slab holder and 25-30 for 20 & 25 slab holder. Latter might be a better option when storage area is not limited.