I had the same problems, the OP was clear what he wanted, and I kept missing it.I had read that part of the requirements without it registering.
The main advantage of my design over what I've seen is every time variable can be set, plus I put a decent DC/DC converter that is a real plus. My 1.1d design addresses all the problems I think, including that of balancing the LED currents and brightnesses.
I got some help from Ron H, the second 555 circuit is a monostable that triggers of both edges, which is cool (Ron's design). The 4th 555 was something Wookie found for me a long while back. The transistor switch configuration was purely mine.