Not that I'm aware of, unfortunately. I haven't followed things much over the past 2-3 years, though.

I suspect there are two forces at play:

1. Building a pure capability-based operating system has minimal payoff. While personally I believe the result will be an amazingly reliable, high performance, secure system, the fact is the operating systems we have today are apparently "good enough" that nobody is interested in funding further work in this area (AFAIK Shapiro and others did form a venture in this regard; what came of it I don't know). Keep in mind that much existing software will have to be re-engineered, and a good part of the OS utilities redesigned since if you're going the pure capability route the significance of files becomes pretty much purely a user thing.

2. At a higher level, in my opinion (as an amateur capability-based systems theorist) the benefits of distributed capability-based systems have already been realised as the shape of the evolving web, albeit on much cruder foundations than those designed as part of the literature. Cookies + URLs are pretty much capabilities, and web services (including web sites!) are effectively distributed objects. Javascript + HTML have fulfilled the dream of being able to ship and run data, code and user interfaces remotely, which is the foundation for an unplanned human + computer usable distributed ecosystem.

Javascript, while not the cleanest language, is a solid language for a capability-based system (in terms of capability rules: everything is an object, objects can only be accessed via references [capabilities], objects references can only be acquired by (a) creating the object or (b) by receiving a capability), i.e. capabilities cannot be forged. If you're interested in what an even more pure approach, designed by people who really know what they're talking about, would look like then take a look at http://www.erights.org and http://www.waterken.com .

In this sense, the first true modern capability-based operating system will probably be the first true web operating system.

I think it's pretty cool, and a confirmation of the ideas in Gnosis, KeyKOS, EROS, Coyotos, CapROS, E, etc. that the natural evolution of the largest distributed system on the planet (the Internet) effectively took the form of a distributed capability-based system.

Thanks, I really appreciate the info. Sorry for my slow response, I hope you see this.

Building a pure capability-based operating system has minimal payoff.

Given the massive security problems we see today, if capabilities are the right solution (are they?), it seems like the payoff could be massive. It seems like "mass adoption" would be hard to achieve (except in the really long term), but it seems like it would be possible to find early adopters who "really really" need good security (e.g. certain military applications, maybe?).

At a higher level, in my opinion (as an amateur capability-based systems theorist) the benefits of distributed capability-based systems have already been realised as the shape of the evolving web, albeit on much cruder foundations than those designed as part of the literature.

This is extremely interesting. Reminds me of the idea behind the "separation kernel" which is supposed to mimic in software the security that can be achieved by connecting systems only over extremely well-defined channels (e.g., the systems are physically disconnected except for an ethernet port that is very well controlled). I can find a refence on security kernels if you're interested and not aware of them already.

Anyway, it does seem to me that there are lots of applications (e.g., embedded applications) where distributing everything over the Internet isn't really going to work (not that you're suggesting that). I'd really like to see people tackle security for this kind of system in an entirely new way. Maybe capabilities is part of that.