I've been looking for software that will allow me to backup my large
amount of data as simple tar archives on DLT tapes for permanent
archival.  This will happen only once and will be the final backup of
the data EVER.  I do not get to choose the type or format of tapes
used nor do I get to choose the archive format (otherwise our
pre-existing Networker backups would be just fine).

Networker can not write to the tapes in a simple tar archive so that is out.

The question comes down to simply this - does Amanda hold any promise
of making this task easier or am I still left to manually breaking up
my 6TB of data into nice 35 - 40GB bites and shoving them at the
tapes?

After a lot of reading I am beginning to suspect that Amanda may be
very nice for day to day backup needs but that the setup for a single,
final backup may be a less than optimal use of my time.