Sorry I couldn't reply to your PM (not enough posts yet, apparently), but I would definitely put the DesignShine Lights out there for consideration for daytime running lights. The taillight really has no equal (even compared to the 400R). When nothing but the absolute brightest daytime taillight will do, the DS-500 is pretty much it.

Here's a couple of good videos:
Prototype DS-500 testing
http://www.youtube.com/watch?v=dRB-6FokXw4

Daytime comparison with the 400R
http://www.youtube.com/watch?v=pVisF...otation_291127

So, on the front end, there's the matching DS-1300 headlight. This is a very unique headlight in that it has the option of an amber daylight running filter that's easily removed (with a single screw). Even with the yellow filter, you could still use it for a see-the-road light, but typically, if you're out on a long ride that goes after sun-set, you'd just take the filter off and keep going. The light has a road-bike friendly mode where you just toggle back and forth between medium and high power. Think of it as "low" beams and "high" beams. On medium (roughly 600 lumens), you still have plenty of see-the-road light, but you won't blind oncoming drivers. The highest power mode, really should be reserved for lonely stretches of road at night, or flashing during the day (1300 lumens).

One thing that isn't mentioned much with regard to daytime running is the "duty-cycle" of the flash. The lower power lights will typically have a much shorter duty-cycle (ratio of on-time to off-time), and my experience has been that the longer duty-cycle at the right frequency is much more effective during the day. The DS-1300 duty-cycle is nearly %50, but you can still get over 13 hours use flashing on high with the 5200mAH battery.

Here's a good video with a ride-by using the yellow lens. Do note that the camera doesn't do a very good job of capturing the yellow tint for some reason. It really is very "other-wordly" looking in real life. If you want to skip over directly to the ride-by, just go to about 4 minutes in.
http://www.youtube.com/watch?v=opt1XI1oatA

Lots more good info at:
www.DesignShineLighting.com
(including the latest Build Blog)
and
https://sites.google.com/site/design...ing/the_lights