Sending a message to users that floats above everything

[hh]

Jonathan wrote:
> What is the best way to send a message to users that floats above
> everything else, including browser widgets?
> ...
> Would it be possible in LCB to make a float-above-everything (including
> browser) dialog?

Didn't read the whole huge thread, so in case it is not already said:

Floating above everything else is easy if everything else is invisible.
So why not hide everything else and display a beautiful custom dialog?