Version:           Unbekannt (using KDE 3.5.6, Kubuntu (feisty) 4:3.5.6-0ubuntu14)
Compiler:          Target: i486-linux-gnu
OS:                Linux (i686) release 2.6.20-15-generic

I do not know if this is the right component to assign this wish to, so correct me if I am wrong.
There is an extension for Firefox called Fullerscreen
(http://disruptive-innovations.com/products/index.html)
which has a fullscreen mode for firefox. Everything (toolbars etc.) appart from the page displayed disappears when going in this fullscreen mode, but reapears as soon as you touch the border of the screen. Something similar is already in Kaffeine if it is in fullscreen mode.
My wish is now to have this implemented as possibility for every KDE application Konqueror, KOffice, Amarok. It may be not usefull everywhere, but where there is a need for a big working area and you have a small screen I think it could be a greet improvement of work flow, especially if you are used to use shortcuts for working and do not need so much toolbars and menus.
Of this course this would need to be configurable in terms of general behaviour and behaviour per application so that users can decide if all toolbars/menus disappear, or may even have sidebars also.
I do not know how difficult this is to implement, but it would be really great to see this in KDE4