It seems like SpringSource is working on EJB 3.1 implementation. This makes EJB 3 technology even more interesting and proofs its adoption. The Spring framework then would be "Just Another EJB Container On Steroids" (JAEC :-)) - it would make, however, the integration between EJB 3 and Spring easier, than even now. This lowers the entry barrier for EJB 3 as well: the migration to pure Spring environment, in case EJB 3 wouldn't be sufficient for functional, or non-functional requirements, should be not that hard.
This is actually the second EJB-container implemented by SpringSource. Pitchfork can be used right now, I'm already curious about the new one. So EJB 3 became interesting enough to be supported by ... the spring container. EJB 3 could be deployed then on: Glassfish, JBoss, Geronimo, WebLogic/Oracle, WebSphere SAP, and Spring as possible deployment platform.
Classic Java EE 7 Workshops: Bootstrap, Effective and Architectures, July, 13th-15th
Online workshop: Java EE 7 Bootstrap