There is no dlt utility shipping with DVDA...but you could prepare the DVD to a folder on your hard drive and archive that to tape (using a 3rd party utility)...or you could archive to a 1394 drive...and send that to a duplicator.
I recently uploaded a DVDA-prepared image to Vaughn (a big duplicator) in Minneapolis for evaluation- they were able to produce a dupe master with zero errors.
So there's not really a problem I don't think- if you have a dlt drive, it must come with some backup tool, so use that to save off the prepared folder and you should be set.