Not exactly.  I already do that with some of my shortcuts and that works.  It's the label/name of the shortcut that I'm trying to do it with.  For instance, I can have a shortcut pointing at "%homepath%" or "%userprofile%" and that works fine, but I'd like to make the title/name of that shortcut dynamic, rather than just "Documents".  I'd like it to be "%username%'s Documents" and I don't know if that's even possible.

Put a folder icon in each user's document folder which has their name on it. Then the Folder will say Simon's in the icon and Documents in the text. Sorted. Kind of.

Do you use any sort of login script manager? We use Desktop Authority and though I've not tried anything like that myself, I'm pretty sure it can do it. It ain't free though. :C