So, there are some pretty good GUI tools for creating, unpacking and browsing BSA archives, but are there any tools that can be driven from the command line? I note that libbsa is being developed, but and once it is a command-line tool could easily be put together using it. I was wondering if anything is available now? For my purposes, just being able to create them would be sufficient.

You can run the CK's http://www.creationkit.com/Archive.exe#Scripting_Archive.exe tool from the command line with a script telling it what to create.

Hmm. Thanks. That might be just enough to get me started.

IIRC BSAOpt has command line parameters.