Evernote
Now I get it...
It appears to me that whenever you have to file something, you create an entry in some sort of catalog software, a numeric one, that you use to label the physical asset. Then on the catalog you "describe" the content by typing tags, a short abstract, or whatever you like.
This would work even with notepad and textfiles + Googledesktop... interesting...
In my particular case, this posts triggered me a wonderful idea. I am giving a try to Evenote software in these days and it might be the good fit for recording the information in the reference file (Note: I am not associated in any way to Evernote).
The way that I plan to use it, is to add a new Evernote entry (hitting Ctrl-Alt-N from anywhere in Windows takes it to it) and type the label of the folder/asset in the first line (it becomes the title). Then write down a number of "tags" simply by typing them below that first line.
So whenever I want to look for something, I can do find for either the tags or parts of the label and voilá, everything appears instantly, as in google desktop .
You might want to build a whole hierarchy of categories that you could add by drag and drop to the new entry while editing it, or you could also define special keywords that any doc that has them, get assigned corresponding categories (eg: if it contains "@cats" it gets assigned category "Cats", and so).
I might agree to type in something like "@ref" to every entry for a physical asset so I can narrow my search to only physical data whenever I want to. I then define a category "Physical Reference" and associate that keyword to it, so whenever an entry has it, I know it's from a physical asset. I can then click on that category and have a full view of my physical reference data.
The beauty of evernote is that is the perfect software for reference information. It has a very nice web-clipper, it's a snap to store your contacts and copy-and-paste any information you come across and find-out to store for future reference (you can do it without going to it, you just edit-copy on the software you are using and then typ ctrl-alt-V and it gets into evernote).
I also use it to manage my @lists also in a similar fashion. I found out to be very productive to have it at the press of a keystroke and be ready to type anything I need, much like those Mac interfases with quicksilver, so I collect instantly what comes to mind and keep with the flow of the task at hand.
Hope this helps. And will let you know how I evolve with this "reference idea".