If I recall correctly, the REB Librarian would do this. I don't think the original site is still up but I'm sure there are still binaries floating around.
There are a number of other ways to roll your own using, say, 'netcat'.
I seem to recall the REB1200 devices being a joy to mess with, with hidden firmware goodies and all.
A quick google search confirms my recollection:
I'm sure someone has the unencrypted roms for 3, and from those you can use the Compact Flash method.