Bratwurst, from the Sega-16 forums, has made his own copy. With a box, box art, a manual (in authentic, faded black & white) and, most amazing of all, he's made his own working Genesis cartridge.
These aren't the first custom productions he's knocked up - there are also copies of Monster World IV and Pulseman out there somewhere - but it's definitely the most impressive. Because it's Alien Soldier.
Alien Soldier Finally Sees US Cart Release [GameSetWatch]