If you want to waste less time reinventing the wheel, why not try a Lisp-machine style terminal system with "live" objects (presentations)? It's proven to work, and many people liked it more than a terminal-based command line. Use polymorphic lines (http://groups.google.com/group/comp.lang.lisp/msg/02782906f6...) to get a very concise, powerful presentation. OpenDylan (http://opendylan.org/) and its IDE/editor Deuce implement these ideas.
