There's been a lot of activity on the L4-Hurd mailing list lately. Looks like they are discussing switching to a different microkernel, a derivative of EROS/Coyotos. Especially interesting is the fact that Coyotos is implemented using a new specially designed language BitC. After all, IIRC one of the major problems with the initial Hurd effort was the difficulty debugging multi-threaded translators written in C. A new language and recent research might make the difference. Maybe a competitor will spark renewed interest in secure modular operating systems.