We will be re-introducing the concept of connectors into 3.1 (see MODE-1513). In fact, see some earlier discussions about how these connectors will be an improvement over what's in 2.x. We've even made sure our 3.0 architecture will be able to do this.
We originally had planned to include connectors in 3.0, but given resources and timelines we needed to prioritize. Most importantly, we needed to focus first on standard JCR functionality and stability. And by pushing connectors to 3.1, we're able to get 3.0.0.Final out faster.
Unfortunately, that also means that people who require connectors (lik you) will have to wait until 3.1. Hopefully you won't have to wait too long, however. Connectors will be the primary goal/feature in 3.1, and we're hoping to release 3.1 about 6 weeks after 3.0.0.Final.
Please review some of the earlier posts regarding connectors & federation. If you don't think your requirements/scenarios are covered in that discussion, please let us know by replying to that discussion.