[OT] dedicating a runlevel for a single app

I want to dedicate a run-level to a single task such that when I boot, at the lilo prompt, I enter that runlevel number, lets say "4", and the machine will not ask for a login but only run this app. When I exit the app it will reboot. I cannot have a login prompt, just this non-graphical app running. I see that Suse has filrewall stuff setup for level-4. I can get rid of that I know. My major problem seems to be the login prompt. How do I get rid of it for only the run-level I want to use for this app? And if I find a way to do it how can I still interactivly interact with the app??? Thanks in advance -- Mark Hounschell dmarkh@cfl.rr.com