No offense intended here, but why would you be storing shared data files on PCs? It seems like you're asking for headaches and having to "pick around" data when diagnosing problems with PCs instead of just blowing the PCs away and reloading them when they have software problems. Data belongs on server computers, with redundant disk and backup mechanisms-- behind locked doors in locked racks and safe from being picked up and carried out of the building / opened up and disk imaged / etc.
Having said that:
Using the DFS management tool, create a standalone DFS root on the server computer. Add the client computers' shared folders as links under the root. That will give you the unified namespace you're looking for.
If you're talking about replicating files out to each remote computer then you'd be talking about DFS replication. DFS replication, however, is only available for Windows Server operating systems-- not Vista (the service is there, but Microsoft never wired it up to anything... there was supposed to be a peer-to-peer file replication service but it got axed and never put back in Vista).
On the other hand, if you're just talking about opening the \server\dfs-root\share-for-workstation-1 path and saving a file there then, yes, when you open that path (assuming you've assigned the "share-for-workstation-1" to the shared folder on "workstation 1") and save a file, you'll be writing to the "workstation 1" hard disk drive.