We have finished porting Inner Circle for Facebook over to Bebo. It was much easier because of our experience porting Doorbell, and the quick updates Bebo has made to their platform to make it more compatible with Facebook. Their goal is 100% compatibility, and although there are only 4 developers, they are making good progress.
Since Bebo doesn’t support FBJS yet, we had to make some modifications to how some parts work, such as the reply page. On Facebook, we can used Ajax to update multiple parts of the page when a user creates a new reply. On Bebo, the default FBML controls only allow an update of a single tag, so we went with a full page refresh instead. Since the page is all FBML, the speed difference is pretty insignificant. Some things we are thinking about for the future are linking the Inner Circles on Bebo and Facebook together. It would be great to know what is happening with your friends on both platforms, all in one place. Anyway, if you are on Bebo, give Inner Circle for Bebo a try.