When Tara emailed me and asked for help in tracking down something similar to the wire baskets in this Wednesday workspace, I used all of my powers of deduction to track down something similar. Tea for Joy Private Investigation services; 100% success rate.
What actually happened is that I forgot all about the question, as I had no idea whatsoever. I was looking at Rockett St George for a completely different reason altogether, and then spotted these. Aren't they fantastic? I'm still in favour of the 'shove everything in a box out of sight' approach, which I'm following on my own desk, but if you're the kind of person who actually gets to the bottom of your in-tray, then these are a perfect option.
Update: Thanks Sian, who left a comment saying she had also seen them here, a little cheaper - and with cheaper postage too. My PI skills are obviously not as good as I thought - although they don't seem to have the letter in-tray.