Handling Errors Gracefully

Is there any way to gracefully handle errors that happen after output to the screen has begun (the point where header(Location:) doesn't work) without using ob_ functions? I have a separate PHP page I'd like to display with the error if one happens using the error_handler() and trigger_error() functions. But, I can't make it work because if the error happens after output starts, I just get an error stating header() won't work. I'm also not sure of the best way to pass all the error data to the error page. Its too much for a $_GET. Anyone have any suggestions or links to articles that explain how this can be done?? Thanks a lot. Monty