For the last year and a half I've been working on a gcc frontend for Go, a new experimental systems programming language designed by a small group at Google. We've just open sourced it. You can read more about it at http://golang.org/ .
The gcc frontend is called gccgo. I've just committed it to svn://svn/gcc/branches/gccgo. The frontend is written in, yes, C++. There are are a relatively small number of changes to the middle-end. Please take a look if you are interested. Ian