You can just use the regular FTP move/rename feature to move the release/dir. ioNinja doesn't care if you move a dir, and nxTools has a rule that fires after the move/rename BUT it is currently bugged. It only processes the directory itself and not any subdirs.
Thus you can move /xvid/name to /archive/xvid/<name> and that will work but won't update the CD1/CD2 subdirs which is a bit annoying since they'll still match site search commands, but moving /dated/<date> to /archive/dated/<date> where there are lots of subdirs won't update any of them.
If you move lots of stuff around this way you'll need to rebuild the nxTools database. Somebody should probably write a fix for this bug
Not sure on the best way to create a .sfv file, but it shouldn't be too hard to find a generic command line .sfv generator somewhere and arrange to call it from a TCL script or directly from an EXEC line with the correct arguments. You likely don't need an ioFTPD specific .sfv generator here.
Update: In the /archive/dated/<date> example, you can of course just create that dir, and then use the FTP move/rename feature on all the releases to have them updated. Just select them all in your ftp client and move them as a group. Each will be individually done by the FTP client so it will be kinda slow but it does work...