Doggle,

I see you already have the DLumotec.
Then a nice combo that works really well from the comments I read on the Randon list is to use a Schmidt E-6 secondary headlight.
Because the DLumotec takes a relatively low amount of power, the E-6 will start to shine at 9-10 km/h and will be bright at 15 km/h. So you'll get a brightly lit mainlight at 2-3 km/h (which is enough to see your way when you are that slow), and at 15 or 20 km/h, you'll have both your DLumotec and E-6 at full brightness; the E-6 will light your main path and the DLumotec will provide spill light to the sides.

As for lighting the trailer, I have to say this is one of the reasons I stayed away from the wired taillights.
My first hub generator dates from 2001. At that time, I was riding my single bike either solo, or with a trailercycle, or with a child trailer or with both. I thought it was simpler to attach a couple of Vistalites on a single bracket behind each of these vehicles. So I went with a 3 W headlight and battery taillights.

Now that we have the newer crop of taillights (TL-LD1000 and Superflash), I have replaced those old weaklings by the new stuff which is about 10 times brighter