lamarca, I'll respond to a few of your points now and save the rest for later. Remember that nothing in this post (or any post of mine) is legal advice; it's just private opinion.

Some good web sites discussing the basics of copyright are

Benedict O'Mahoney's Copyright Basics. This only discusses some topics, and hasn't been updated to take the Sonny Bono extension into account;

Professor Terry Carrol's Copyright FAQ. This also is not yet updated for the Bono CTEA, but Prof. Carrol does provide a page of updates.

Patents currently last for about 20 years. I say "about" because there are two ways of figuring the term, one (20 years) from when the application is filed, one (17 years) from when the patent is issued. I'm not sure which applies under what circumstances. A copyright is a weaker monopoly than a patent, so it is arguable that a copyright should last somewhat longer than a patent.

A common practice in publishing was for the author to sell the copyright outright for a lump sum. Now the common practice may still be to sell the copyright, but in exchange for a royalty contract. In any case, except in a work-for-hire situation the law grants the copyright first to the author. But for the author to transfer the copyright to a publisher is I think fairly common. (Scholars in many fields usually transfer the copyright to the journal-publisher without payment. Some musicians may set up their own publishing companies, in which case the transfer is out of one pocket, into the other.) The copyright notices you have seen in which the publisher is named as proprieter may represent cases where the copyright was transferred from author to publisher. The notices where the author is proprieter might represent cases where the author was in a strong enough bargaining position to insist on retention of copyright, or perhaps they simply indicate that different publishing houses have different practices.

Maybe there are some authors and songwriters on-list who have more experience of commercial publishing than I have had, who might be able to give you the inside scoop on publishing house practices.

Besides this there is a legal doctrine known as work-for-hire. In certain circumstances the legal author is not the human author, but the author's employer. Films are commonly considered works for hire in the U.S., but I think books sometimes qualify too. Some of the copyright notices you have seen in which a publisher is names as copyright holder may be in works for hire.

T.