The Net has definitely made some shockingly niche goods available to the narrow markets that want them, like these BrickArms Weapons, realistic weapons for your Lego army:
BrickArms are designed using the latest Computer Aided Design (CAD) tools to allow for precise details, and yet still retain an artistic sculptural feel of the action weapons.Injection molded to the highest of tolerances, all 21 BrickArms Weapons are made of durable ABS plastic — the same plastic that Lego uses in their own toys, to mesh perfectly with the Lego system you already own.
If you have any doubt who their market is, note that the rifle pictured above is an X41A “Xeno” Pulse Rifle — “Hicks tested, Ripley approved.”