I'll have to update myself on DragonFly in near future. Good that you know about EROS and Capsicum: ahead of most ;). Check out CheriBSD on CHERI processor if you like that. Far as software, JX Operating System and GenodeOS are two clean-slate one's with architectures you might find interesting. Interesting in terms of foundations to build better stuff on.
Oh yeah, there was a talk about CheriBSD at this year's BSDcan. Gotta look more into it. GenodeOS looks fascinating from first glance. I'm aware of the various JVM-based OSes, but I have no personal interest in them. Thanks anyway.
