I would not be surprised if we had to wait till the end of the year for a first stable release (4.1). A new backend architecture is a challenging major undertaking. That means each module must be analyzed and taken down for a complete rewrite. The announcement page states there will be no major changes on the interface side, but keep in mind that does not mean the front end will just run on the same ext code - I am sure it required a lot of attention as well. Hopefully once this milestone is complete we will have a rock solid foundation to build on new modules and extend the existing ones in an organized and standardized manner.
Though I too would love to know if there are any news, perhaps estimates on the released date (we just closed the first quarter of 2012