We use the tvp5151 with an overo for NTSC capture with the 3.5 kernel. The nice thing about the 5151 is that it doesn't require level shifters.
We made a few small changes to the tvp5150 driver to work with the 5151.
If I remember right, the bt656 patches for the OMAP isp driver came from Laurent Pinchart's repo. .
Everything works with gstreamer just fine, although the video still shows the interlacing artifacts/ghosting during high motion.
I would be willing to come up with a tvp5151 board which could connect via ribbon to the overo if there is enough interest.
Laurent has suggested before that if he had test hardware which supported bt656, we would get better support for it.