Step 1: Modifying The Frame
Step 2: Hitch Mechanism
Step 3: Attaching to Bike
Step 4: Safety Light and Battery
I found a piece of old plumbing drain (a "T" joint) and mounted 2 small side lights and a 4" LED light I found at Harbor Freight (I love that place). It's all epoxied together and sprayed black. The drain T slides right over the seat shaft for a snug fit. There's a hole in the top for a flag staff. The wiring ends with a cigarette type connector for fast disconnect. I used a $3 blinker inline to make it flash.
I have a 12v lead acid battery from my photo flash equipment that can be recharged and is light enough to strap to the rack over the back wheel. You could probably use a bigger one.
Step 5: Carrying Options
CAUTION: This will not hold a person. Small dog, maybe. Trip to the store, most definitely. Trip to town or the beach with food and tune, yes.
Have fun and let's see what you can build.