This is your light: NiteFlux RedZone 8
I ride in NYC, home of the dreaded yellow cabs and apart from the vis180 on my helmet I use the RedZone 4 on my backpack and it is brighter than the Dinnotte 400R, plus its much lighter, super rugged and shines at full power beyond 180 degrees. This is the without doubt the best rear light available. The RedZone 8 takes it to airport level lighting.