I would make a full gamedemo that gets updated with
the newest functionupgrades - when the compensation is sufficient...
In fact, Conitec is providing functions, and test them
in very small environments if they work technically correct.
For 90% of these functions there is not full game needed to test them.
For other things such as if a workflow (WED, MED, Modelimports..) on a large scale works correctly/conviniently,
they rely on the user feedback.
An A7 game demo would rather have the sense to promote the
engine directly, also given that the sources and code are
open for everyone to test around.
Its not really neede to test if the functions work correctly.