I’m looking for a red dot type of optic in which when the battery dies, what is left is a black dot. This way, you don’t need to co-witness iron sights. 
I know the Russians got one. Is there a US made version for picatinny rails?
I don’t think this is an ideal solution. The modern aimpoints have a battery life measured in years, and are extremely durable.
Some of the reviews on the prismatic list durability, brightness and battery life isses.
I’m not sure…but I think the Leupold prismatic optic is not a non-parallax optic…not a 100% but i fiddled around with the mini trijicon acog 1.5X optics…granted they had a slight zoom to them, but I think the same concept applied to the trijicon and the Leupold here, the trijicon was def not non parallax
also…speaking of trijicons…http://www.cgwgun.com/Trijicon-TriPower-Reflex-Sight__TX30.aspx
that maybe your best bet. they work well, are non-parallax and have multiple back up sources
What are you using it for?
According to the Leupold catalog the prismatic has a parallax set to 75 yards. I have played around with them. I like the etched reticle idea but other than that don’t know too much about them.