Finally! I discovered what the problem was with Ubuntu and old versions of Python (I had to create symbolic links for libz.so.1 and libreadline.so.5 from /lib/x86_64-linux-gnu to /lib). That resolved all of the problems I was experiencing with the older versions' interactive shells. I also re-created the test script that automates feedparser testing across Python 2.4 through 3.3. All that's left is to install coverage and sphinx again.

I've also made it a goal to work on bug reports almost every morning, so the issue tracker is shrinking back down. I'm abruptly back on 12 hour days at work and my weekend is in jeopardy, so I think I'll push a new release as soon as possible and then begin pulling in new features and making larger changes.