Now that Lightning 0.1 has been released, there have been a fair number of people asking about plans to release a Sunbird 0.3a2 as well. We are indeed planning to make such a release as soon as possible to have a Sunbird release similar to Lightning 0.1. Today we reached 205 bugs fixed since Sunbird 0.3a1 was released and we definitely want our users to have these fixes available in a stable release (as opposed to a nightly build).
Currently, we have a rather short list of bugs that are blocking the release. These are listed in the tracking bug. Keep in mind this list may grow or shrink, depending on various discussions concerning the goals of 0.3a2 and the best way to strike a balance between more bug-fixes and a quicker release.