OK, we've been suggesting guns - how about ammo?
.30 Rimfire
.32 Rimfire
.41 Rimfire
.43 Mauser
...and on and on and on. Runs of 10,000 of each of these should sell out in well under six months. There are no other sources for this stuff, and a lot of fellows have been buying antique pistols and rifles and either hand-rolling their own ammo via mystical ancient methods known only to the Cognoscenti and certain high-level Masons, or simply letting those old ladies lie silent.
I know importing ammo is a lengthy and painful bureaucratic process, but I reckon a guy could make some money with this... And if loaded ammo is an issue, what about primed rimfire cases and bullets?