Just finished up what I think is a tiny bit of a different take on the modding of toy guns.
Here's a Nerf nitefinder converted into something similar to a Las/Auto Pistol. The goal was an easy mod that would look
40k'ish, and shoot a beam of light from the barrel. I think I accomplished that by completely cutting away the targeting mechanism and ammo holder under the barrel and moving the targeter-light-beam into the actual barrel.
You can see the complete how-to on our club's blog here...
http://chicagoskirmish.blogspot.com/2012/10/build-your-own-11-scale-laser-pistol_15.html
...but here's the pics of the finished product.