I didn't like the wooden saddlebag style racks on my Piaggio that I had originally made. The problem was that the Piaggio didn't have adequate mounting brackets for them, which meant they were putting strain on the rear fender. Also, they interfered with the pedal action.
I decided to change the mounting system to a rear rack style. I removed the elongated double seat and replaced it with a bicycle seat. I used my MIG welder to bodge up a rear carrier, seen below. I think it looks pretty good.
More postings to follow re: the decision to change batteries and the actual battery carrier itself.