Check this out!
http://www.youtube.com/watch?v=GJM8asnj6JY&feature=related
Sweeet!!!
Prototype only… If you could get your hands on one you’d be rich but you probably have better odds of winning the lottery.
Spooky
Made originally for the AN-94 IIRC. I tried getting one for years to use in my AK-74’s but no dice. My Russian supplier “disappeared” before he could come up with one (sigh…)
Tomac
Someone is at least trying to build one.
http://www.ar15.com/forums/topic.html?b=4&f=55&t=107952