An impressive trick at Commodore users group meetings was to run Fast Hack'em for the 1541. This was a low-level floppy copier that ran on one or more 1541s, without the need for a host C64 once the process started.

i.e. you'd start connected like this: (drives were daisy chained)

  [C64]--[1541]--[1541]

Then remove the C64 and dupe away for the rest of the evening, swapping in disks as they completed.

  [C64]  [1541]--[1541]