Apart from the syntax and our current lack of a REPL outside of Windows, Dylan (http://opendylan.org/) sort of fits in that space. We're a lot like a slimmed down Common Lisp (designed by some of the same people that standardized CL), and bigger than a Scheme.

We're currently working on a lot of stuff, including an Objective C / Dylan bridge, a new build toolchain and an experimental REPL that may work outside of Windows until we can bring over the real one (once our LLVM backend is in place).