Why get something different for the second light? Get another Cygolite 750. Mine came with both bar and helmet mounts and I use them both ways. You can run on low and the other high, one flashing the other steady, etc...
That is what I decided to do. the 750 is more than is needed on MUPs and could be used on a single track. The extra light mounted on a helmet will make it so I don't need to slow down in the turns. Down the road, I'll pick up an extra battery.
Since I have no friends who night ride, I can now bring a guest.
Thanks for the ideas!! This is what it should look like
http://www.youtube.com/watch?v=jY59UxUGG0I