How about some Whelen tir3 modules, or similar, wired into your homebrew system. They come in all sorts of colors. They're made for auxiliary emergency lighting for police car mirrors, tow truck bumpers, etc. etc.
Personally I use both of my Fenix P3D's (one bar mounted, one helmet mounted) in strobe during the day and on turbo at night. Just had a co-worker today tell me he saw me while he was parked on the side of the road when I was several streets back (at about 2:30 in the afternoon). Definitely not getting doored by him, heh. I also had a truck driver think I was trying to pull him over once. Obviously he doesn't know the only light drivers are required to pull over for in California is a forward facing red light (steady burn or flashing). I've found the helmet light on steady is enough to get everybody's attention at night, and I think a really bright flashing light facing forward would distract me at night.