The "nandroid.md5" file that accompanies the backup .img files only lists the filenames and MD5 hashes. There are no paths to the image files included in the MD5 file.They are listed by date but if you have multiple backups its sometimes hard to remember witch is witch but if you had the option to rename them before the backups was mad the Mds. would match and the backup would work.
So if you just rename the parent folder (not the individual image files) then the restore should still work... no?