Does anyone know of a multi-file streaming archiving tool that can accept input from pipes, FIFOs, or commands? #tar can do what I want for output with -O, but not on input, because each file's header contains a size, which of course wouldn't be known for streaming input. Must be able to separate files back out again on the other end.

The closest I've come is #uuencode, which can concatenate output and #uudecode will identify the individual components - but of course it has a space penalty.