I have a question and a suggestion, (if it is okay to have both
When you say "desktop icons" are you referring to document files on your desktop or short cuts to the applications you use?
Suggestion: (assuming you are referring to document files)
In Windows XP and on, you can group documents in a folder by date by:
Switch to Details View
Select View - Arrange Icons by Modified
Select View - Arrange Icons "Show in Groups"
This puts a few vertically arranged categories up for you: Today, Yesterday, Two Months ago, etc. So what happens is, is that your icons are grouped by when you worked on them last. I use this for every folder I work in and it works great. It sort of follows the Nogouchi file system you mentioned.
The only problem is that you can't use this view on the "Desktop" per se, unless you open a windows explorer window, and then open the "Desktop" folder from there.
Hope that is helpful.