I can't think of a workaround that isn't weird/counterproductive. Your approach would suffer the same problem as the following: in order to see filesystem changes in audiosurf's file browser, you would have to exit out of a folder and reenter that folder.
How about something that can generate a .m3u file from your collection, in shuffled order, so you can finish a song and be forced to play the next

, or if you don't want that song, you can re-generate the .m3u file and then re-load the .m3u file in audiosurf... I can write a script that can do this.
But this leads me to want a feature of being able to browse the contents of a playlist file (and also want audiosurf check it for changes and in the filesystem for the current folder, so you don't have to do the aforementioned odd steps to refresh)...