I've been working on something that sound's like what your asking for. When linux starts it opens up some daemons and then starts a gui. (gui is not any where near complete) The gui is just basicly and xml document defining screens and buttons and actions for those buttons and the image to use for the buttons. It uses directfb so there is no X windows to install.
By the way I've been reading this forum for several months now (and now I finally decide to join in) and this place totally kicks some major ***.