Thanks everyone for your replies.

Ethan, I'm glad to know that xEAC can handle the creation/deletion of
relationships between persons in multiple records. That's a major plus over
editing by hand. Any plans to handle modifications to the relationship in
multiple records?

Jessica, I tried out the demo of ICA-AtoM and am impressed with the clean,
snappy interface. I wonder, are there plans to support some of the more
complex EAC features, like placeEntry URI's, event lists, language and
script tags for individual name entries, localType attributes, etc.?

I've looked at Archon and will keep it in mind.

Jen, we are the Syriac scholars--which is why we're looking into this :-).
We not only have authors that we're working with VIAF on, but also saints
and persons mentioned in historical texts. So we're trying to figure out how
to best create all these records.