Been perusing the offerings from Serfas. Two lights catch my eye- the 'Shield', which is over my budget, and the TL-200, which looks like to be of a similar design to the PDW DZ.

What I like about the Sefas site is that they offer up a video of each of their tail lights in action. It looks like they used the same route and moved at similar speed in every one of the vids- they just couldn't control traffic or weather.