I thought this was pretty cool. This Sub-2000 owner modified his fore stock on his carbine to hold a spare magazine and a flashlight, this could work for other guns as well....
You could also get this factory spare magazine mount from Kel-Tec
There are a few Glock floor plate options out there, my two favorite are the Magpul Speed plate, a smaller version of their Ranger plate that fits AR magazines. On the shorter grip frames this can also act as a finger rest.
The second one is the Fab Defense picatinny floor plate, it allows you to invert your magazine and turn it into a forward grip. This was what I installed on my Sub 2000 carbine (I used the 10 rounder that came with the gun, 17 rounds would've made the gun a bit too nose heavy)They also make them for the Beretta M92, CZs and CZ clones...I may have to pick one of these up for my Beretta Cx4 Storm Carbine
Wild West Guns in Alaska is famous for their custom Marlin Guide Guns. They turn the model 1895 into a take down model and add special features like the large lever loop. They call this the "Co-Pilot".
Bird's Head grips are normally found only on Single Actions and 19th century pocket pistols, here is a modified Ruger double Action .44 Magnum Redhawk with a bird's head.
Conversely the "Fitz Special" modification to the trigger guard was only done on double action Colt revolvers, yet here we see it on a Single Action
MFI Battle Star Galactica Barrel Shroud for Beretta CX4 Storm (9mm), I installed one of these on my CX4 Storm, see it here
This has become popular, having the end of your barrel, recoil spring plug or barrel bushing engraved with a clever slogan for the goblin who will be staring down the business end of your pistol
This one comes from Kinetic Concepts Tactical, adding plastic windows to your Ruger BX-25 10-22 Magazines. They even added numbers so you can see just how many boolits are left inside.
While on the subject of 10-22's, how about a 10-22 Charger converted into a Pirate Pistol?
How about modifying your factory 10-22 birch stock instead of buying a custom one?
Robar can provide a factory looking beavertail for your Glock pistol, also check out the rear sight:
This Glock mod is not so permanent, from Fab Defense/MAKO is the Tactic Skin slide cover for Glock pistols
using the same concept is the Recover from Recover Tactical. It allows you to cover the frame, add a picatinney rail as well as a grip.
Originally just for the 1911, they now make them for the Beretta M9/ model 92
Universal Bayonet mounts have been around for awhile, but they were mostly for rifles, now Remington shotgun owners can mount a bayonet to their 870 combat shotgun.
This one, performed on a Ruger Single Six, was done by a friend of mine (and fellow gunsmith) Tactical Assault. He cut a recess into the backstrap and added a pin for a lanyard.
Adding grip tape, skate board tape or some other such material to your .22 varmint gun....a good idea...I might have to do something like this on Project Night Prowler
Kinetic Concepts Tactical
Hipshot on Rimfire Central
Bowen Classic Arms
The Smith Shop