Not to detract from your suggestion, but 2 solutions occur to me.
1. Use the Windows Disk Management tool to change the drive letter assigned to the removable drive.
2. Use the example referenced here
http://kinook.com/Forum/showthread.php?t=2825 to do a global search and replace of the drive letter.
Now to your suggestion #1...I also keep most of my files carefully curated in folders on a virtual disk D: I have noted (with a little concern) that Microsoft, with each iteration of windows, seems to be moving us away from drive letters (and even thinking of files as located on a single physical disk). This is not really surprising, remembering that the file system is just another database. At a technical level we can use virtual disks, spanning disks, junction points, etc. At a user level we now have Libraries-- which are like folders, they show me files, but different because the files are in different "locations". Perhaps UR will be able to use/create libraries to reference our documents in a manner similar to your suggestion. (Currently of course, I can use a simple solution and store my documents in UR where they travel hassle free)
-$bill