Just found the coolest thing: http://airowgun.com/paint.php
It's a device that converts a bow into an air rifle. The "arrow" is in facta piston. Shooting this "arrow" compressesair into a rifled tube. Ergo, an air rifle. Pretty impresive performance too.

So, how about this for crossbows? CB is far more "natural" for such application. The short stroke is also beneficial. Not to mention how great that deck groove will be for the barrel.

High five?