We had a "happy accident" recently. We collect plastic, wood and other trays from area businesses for "recycling" into hobby and craft uses. One set of trays, with a fairly steady supply, we'd been using as sorting trays, but they were an odd size, and not really amazingly suited for that purpose.
But, during another moving around of inventory, we found that our flip top tubes fit *PERFECTLY* in the holes, and we started to use them to count and hold inventory.
Then, we had several filled trays, and it would make sense to be able to stack the trays, but we didn't even consider that the lids would fit back on. I set the lid on the top, just to see if it would provide a level surface -- and not only did it fit -- it fit *PERFECTLY*.
Things like this just don't happen!! A very inexpensive, durable, and pletiful item, that has a use, without compromise! The lids fit tightly, and snugly over the top of the 1-7/8" tubes, and "lock" them in place!!
We can offer these trays *free* (only shipping/extra shipping) with any purchase of 10 or more filled tubes of beads, or 100 empty tubes of beads of any sizes! (Our three smaller sizes will fit into the trays, with at least a few of the 1-7/8 tubes to help support the lid if you are going to stack them! The 4-3/4 tube does not fit under the lid, but can be held upright for working by the trays.)
Here are some photos. Prices without tubes or orders are $4.99 each, and we have about 20 of them in stock at the moment. They interlock, so for shipping or empty storage, they compact down pretty well. Because of the size box, you need to figure the 2lb priority rate shipping, and probably 3 (maybe more ) could go for that single rate.

above: in our fliptop storage / worktable system..



Shows how they stack, partially interlocking for a stable stack of 3-5 possible.