If such need is common enough, we may provide a special environment,
much like "againframe", which would provide a frame without title. For
example:

* Headline
:PROPERTIES:
:BEAMER_env: fullframe
:END:

What do you think about it?

That would be definitely nice. I think it is quite common that you want to get rid of everything to have more space for a big drawing

(moreover it breaks the monotony of the layout)

Fabrice