I have an idea of an app - sort of. I would call it StealthMode. Idea is that it would be a theme that would change the desktop black as well as lockscreen and the desktop would be without apps. So nothing could be seen if you try to unlock the phone and nothing either if you get to desktop. For the top bar to be shown or the application page you would need to use some certain keys so that hitting the upper corner or the top of the screen would not bring anything to screen except open apps. When you would install the app and launch it you would make shortcuts to number keys. The app should make it to be able to launch apps by typing the apps name or using shortcuts and pressing enter. After one saves the settings in the app you would launch the stealth mode by typing StealthMode and pressing enter. In the lock screen you should also be able to give passcode with keys and pressing enter. If you would want to be exposed again you would type ExposeMe and press enter. The apps would work normal and show the top bar and other stuff normally.

So why dont you implement it ? Go for it

Not a developer. No coding skills. Just learning a bit QBASIC. That's all.

Didn't see that.... did you now?
I was just here...using my stealth app...
actually it isn't really an "app" per se ...
More of a technique I lifted from an old sherlock holmes story ...involving writing invisible ink letters in lemon juice...so once dry they disappear..until the paper is heated...and then the words become visible again...

So step one...
grab your n900...a basting brush and a jar of lemon juice...

Step two...
Baste.

Step three...
allow to dry...

once dry ...
Step four ...you should be able to stealth surf with anonymity ...
(although you may find the slider and keys sticking a little..)

once done and you want to come out of stealth mode...
Step five...
Light a fire and hold your n900 over the flames with your bare hands ...
the screams you make will definitely be less than stealthy.....signifying you must indeed be out of stealth mode .

(jeez I am on a roll today...I should really monetize myself and get this stuff syndicated...)

I had forgotten that. But now when you reminded me I remembered I had done just that to my old computer I had losted. So I went back to my warehouse to walk a bit and hit my toe to something invisible. Took a hair dryer and voila, I got my computer back! Thank you so much! From now on if I ever use that lemon juice trick I will definetely add some odours to it so it is easier to find.