Simplepie 1.3.x used to provide the "compiled" monolithic version directly as a download on the website, which was quite convenient.

I saw this in README.markdown in the 1.5 tarball today:

If you'd like a single monolithic file, you can run php build/compile.php to generate SimplePie.compiled.php.

...except the build dir doesn't exist in the release tarballs, so I thought it didn't exist at all, until I found it in git master. So I would think either the compiled form should also be available as a download on the website, or the build dir should be present in the released tarballs, or the README.markdown file should explain where to get it exactly.