I have honestly become lost in this thread, seems to be alot of back and forth. In the end I tried doing this myself, and its worked perfectly as far as I can tell. Here is what I did.
In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{1A6FDBA2-F42D-4358-A798-B74D745926C5}, the parent folder variable points to {48daf80b-e6cf-4f4e-b800-0e69d84ee384}, which is public libraries.
By checking similar entries for the other default libraries, you find that the folder variable for the user libraries directory is {1B3EA5DC-B587-4786-B4EF-BD1DC332AEAE}.
So I copied the RecordedTV.library-ms file from C:\Users\Public/Libraries to c:\Users\username\AppData\Roaming\Microsoft\Windows\Libraries, and then changed the parent folder variable as above, logged out and in again.
The result is that Recorded TV now acts just like all the other default libraries, clicking in start menu points to the correct location, and it displays correctly in navigation pane.
The library can now be renamed and used for another purpose, bringing the total of private libraries that can be accessed via start menu to 5. This is the max as far as I know, I have still not found any method to add custom libraries to start menu from scratch.
Using the Zorn Software tool, located at
Zorn Software » Blog Archive » Win7 Library Tool - Simplicity is the Essence of Good Design, these libraries can now be linked with network locations as well.
Edit: One thing that is still wrong are the tooltips displayed when you hover over the library links in the start menu. They display the default messages. Anybody have any idea how these can be modified?