I had the chance to visit with some of the good folks at Great Lakes Tactical (GLT) last week. Based in the Cleveland, OH area, GLT manufactures a variety of suppressors, AR parts and Glock goodies.
One of the things they brought to the range was a G19 equipped with a proprietary giggle switch. The switch allows the shooter to swap from semi-auto fire to full auto with a cross-bolt type switch. Full auto can quickly overwhelm the shooter, but three to five round bursts can be managed easily with a good grip and stance.
The switches are not expensive, but GLT will only sell to other companies or individuals licensed as manufacturers of full auto weapons.
The company does sell a variety of other Glock parts that are non-regulated. They recently rebuilt my second generation Glock 19 that had been subjected to the effects of bad gunsmithing. The GLT striker and guide rod both run 100% reliably in my gun. Also, the Melonite treatment on the slide and barrel looks outstanding.