When I first began trying to market my novels (before I realized how important it is to have an agent), publishers had already begun bricking up their transoms. The number of houses that would accept even a partial un-agented manuscript was very small. Two of the houses that had abolished their slush piles were Ace and Roc. I'm not sure if they were part of the same parent company back them, but they are now, and they both have what I think is a new policy (or at least it's new to me). According to their Submission Guidelines, writers can now send either an e-mail that contains a query letter and the first ten pages of the m.s. (in the body of the e-mail, no attachments), or they can snail mail a query letter, a short synopsis, and the first fifty pages. The hard copy route gives the writer more room to work, but it also has a much longer projected response time (12 months versus 3 months). The editors express a preference for e-mail. This is almost as good as Tor, where they take three chapters and a synopsis.
In the old days I would have gone for the fifty pages and waited the year, but now I'm not so sure. If you can't sell them in ten pages, you probably can't sell them in 50. Of course, that could depend on the story, too, but who's to say they will read all 50 pages just because they let you mail them that many?
Anyway, this is good news for folks who want to try to get published the semi-old-fashioned way. The electronic transom is now open at least a few inches.