As if I didn't have enough other projects on my hands, I've just put enough finishing touches on Cankiri to release it into the wild licensed under the GPLv2. It came about after looking at Istanbul around version 1.2 and being disgusted with the limited features and overengineering in the code. Come on, you don't need two directories and at least five files for this functionality. Really. Since then both Istanbul and I have added screen area selectors and audio recording. I've got all my code in one 400 line file; Istanbul now spans many more files. Where this really shows: ls -l.
It's amazing how concise you can be with python once you know what you're doing. I hope you find Cankiri easy to use, as a single-file distribution leaves no room for documentation. Let me know what you think.
(All the jabs at Istanbul's code aside, I'm very grateful for the GStreamer plumbing I've been able to take and reapply. Since I've yet to really learn GStreamer, this has been critical for me.)