Well, after reading this description of Vista's virtual folders:
http://winsupersite.com/showcase/winvista_virtualfolders.asp
... I don't think the MS implementation will work for me. I need a generic container. Vista creates a system query.
The problem with the query approach is that there would have to be something in common in the metadata of all the files in the virtual folder. Such as filetype, author, bitrate, or whatnot.
This means I would have to actually enter or algorithmically populate the metadata in each one in order for the virtual folder "query" to find the designated files.
For me, that would be ok in some circumstances, but not in most others.
The virtual folders I envision could contain such a hodge-podge of files that they would probably not share any generic metadata expressible as a query criteria. Or at least the query would be so complex as to be unproductive to create.
In most circumstances I just want to drag files into a "static" virtual folder... or maybe do something like creating a zip file: Select the files, "virtualize" them, type a name/location, press enter.
On the other hand, maybe I need to rethink my own process. Perhaps a metadata dialog would completely replace the copy dialog we are accustomed to...