"Of course, this only works if the buying company is really not interested in, and ignores, the Arsdigita brand."
take a look at http://www.akopia.com , which was an ecommerce package that was bought by a certain linux company.
The brand name died, but the acquirerer kept the domain & just redirects to their site. So.. even though the Akopia name isn't being used, you can't really name another product Akopia without generating confusion.
