2 things:
1) The easiest way to let dwarfs use blow-guns and their respective ammo is to add this underneath the crossbow weapon thingy under [ENTITY:MOUNTAIN]
[WEAPON:ITEM_WEAPON_BLOWGUN]
[AMMO:ITEM_AMMO_BLOWDARTS]
2) For style points, dig out a long, 2 tile-wide hallway. Put a 2x2 square of upright spike traps connected to a pressure plate, and fill the traps with menacing wooden spikes, 10 per trap. Then, place the blowgun traps--again, ten blowguns per trap--in that same hallway, like this:
|:Wall
B:Blowgun trap
.:Floor
|B.|
|.B|
|B.|
At the end of the hallway, carve out a 5x5 chamber. Put a pressure plate in the centre, and connect it to lots of stone fall traps in the chamber. Place an artifact (or masterwork) golden figurine of a forgotten beast on the plate. Fill the chamber with blowgun traps in the same checkered pattern in the hallway. Abandon, and come back to the fort in adventure mode. Make your way to the hallway, and pick up a couple of handfuls of sand and put them in a bag (bag, NOT your backpack). Make your way into the hall, and be careful of where you placed the traps in fort mode. Make your way carefully through the chamber, adjacent to, but not directly on, the pressure plate. Drop your weapon(s) and shield(s), and 'r'emove the bag of sand from your pack. Stand on the plate, pick up the figurine, and immediately drop the sand bag. Grab your weapon(s) and shield(s) and GET THE FREAKIN' HECK OUT OF THERE. Run straight through the dart traps and out of the hall. Now all you need is a massive boulder to come roll after you, an arch-nemesis to take the figurine from you, a horde of angry warriors shooting at you, and a flying mount, preferably with a trained pilot who has a pet snake. If When this is possible, jump onto the mount, fly off, and shout this at your pilot: "There's a big snake in the front seat of the plane saddle of the mount, Jock!" or whatever your pilot's name is, and have him shout back: "Oh, that's just my pet snake Ritchie!" and shout back "I hate snakes, Jock! I hate 'em!" Have him shout back: "Come on! Show a little backbone, will ya?!?" or something along these lines.
See what I'm goin' after???