Have you considered removing the
direct write from tar as a bad idea as people over write it all the time with
formatted data on hard disks and even tapes using a different program that uses
a file system as the direct write doesnt show up. The streaming function could
be moved to a separate program that reads a specified file and streams it to a
location or device.
This would work with multimedia on internet servers which would just read
locations to stream to from a pipe with a add or drop so a common file could be
sent to multiple addresses.