I'm writing a prototype-based, capability-secure, completely dynamic programming language in the style of Smalltalk, with the goal of having a language flexible enough to write anything from small utilities to an entire computing system. The language aims for flexibility and scalability. As of now, speed is only a secondary goal. Sun was able to get Self code to run half as fast as optimized C, so speed shouldn't be a long-term problem.
The VM is being written in C, and is in the early stages of development. Once it gets to a roughly usable stage, I plan on making it open-source.
Features
Prototype object-oriented: Everything in the system is a first-class object which accepts messages.
Capability-secure: Any object can have its access to the outside world arbitrarily limited, and access to any object can be limited. A path, like Unix's, replaces global scope.
Image-based: Every object that a program creates may be kept in an image for suspending and swapping with large data sets. The default image formats are cross-platform.
Garbage collected: All objects are fully garbage collected. There is support for weak pointers and collections.
Just-in-time compiled: Bytecode is compiled to native code before being executed for performance.
Multi-paradigm: Procedural, functional, object-oriented, and concurrent paradigms are included. DSLs are easy to write.