I feel Muji should be the place for this, but their website's a bit rubbish - can't find what I need - all their A4 storage things seem to be fairly shallow drawer type things, whereas I want something more shoebox-ish.
I do want something that can be on display - the Really Useful Boxes are a bit unattractive altho I'm sure they'd do the right size.
They're for DH and I to use as in-trays that we can stash either in a cupboard or a shelf in our shared home office - the idea is that if either of us clutters up the desk, the other can chuck all their stuff in their box - which is why something really shallow won't work.