I have test ridden several trikes and have been amazed at the comfort and speed. I am hesitant to ride one around here, mainly due to the narrow width of the roads, traffic volume and insane redneck drivers. FWIW I have seen little lights that could be mounted on the end of the safety flags, I just don't remember where and what they were called. Perhaps the FireFly lights like people put on their valve stems would work.
Aaron