The Caml language is another memory of the ML family which tends to require fewer restores than Standard ML will providing most of the benefits. Oberon is also an operating environment which runs standard alone or on top of a traditional operating system. Oberon proves that it is still possible to make a fast, small, and functional systems. The portable object files are cool. Unfortunately, while Oberon environment lack features that most large scale projects require.
Self is a pure prototype language.
I am not sure that anyone is really using Self anymore, and there were very few groups which used Self for real work. TK is a very nice X11 toolkit. Tcl Resource Tree maintained by NeoSoft has a good collection of resources. The object interfaces provided by ILU hide implementation distinctions between different languages, between different address spaces, and between operating system types. It can also be used to implement distributed systems.