i'm working on a similar project using rhino 1.7 on the jvm.<p>i've added a pretty seamless package management and script loading system on top of rhino (you can say 'package('foo.bar.baz')' and it does what you expect), and done a servlet that will invoke scripts written in it.<p>on top of the basic language and servlet infrastructure i've written a little glue to allow seaside-style continuation stuff, except that the continuations can be serialized and consumed inside another process so it can be clustered. i'm deeply indebted to attila szegadi for many of the techniques used to do this.<p>it's very cool (and quite fast/scalable) and js 1.7 is actually a very modern and powerful dynamic language (lexical scoping, comprehensions, generators, etc.). my company is in the process of open-sourcing it but if anyone wants a sneak peek let me know and i'll ship out a tarball.<p>oh and libraries aren't an issue, i've gotten everything i've needed by calling into the standard java library. we've written real applications with this thing.