Where to get a Yaffa Block top?

firefIy

This is random...but I'm working on Baby's closet today.  We have a bunch of old Yaffa storage blocks (like egg crates) that we're stacking in the closet.  I'm trying to find somewhere I can order or buy a top for the stack of blocks.  We have one, so I know they make them.  Anyone see Yaffa blocks in stores lately?  I checked Walmart, Amazon, Ebay and Lowes online.  Maybe they just don't make them anymore.  Thanks!