Interesting. I can just see it now: DBD::FTP, DBD::HTTP, ... ;-)

That's actually not a bad idea. The trick is how to make FTP and HTTP interactions into a SQL like dialect. For inspiration, take a look at DBD::Google and the more recently released DBD::iPod, or the older, and kinda funky DBD::Chart. And actually DBD's are not really as hard to write as you might think. There is plenty of good documentation, and solid implementations out there which you can work from. Personally I always look at DBD::mysqlPP whenever I need a reference, the code is really clean and very easy to read.