#5 is a hybrid petrol-electric tricycle built by Avery Petty from Riverside, California. It doesn't use batteries, but has a 5 kW petrol generator driving two DC electric motors (hang on, weren't Tilling-Stevens doing something similar over 100 years ago?).
Anyway, the vehicle is street legal, does 30 mph and 90 mpg, and is, according to its creator, awesome.
In fact he likes it so much that it's for sale at the moment at $10,000, though the advert claims it cost nearly ten times that to build, and took 4 years. According to his Facebook page, Avery is a cashier at Walmart - they must pay better wages than shops do in the UK. Best be quick. I can't see this baby sitting around for long...
http://www.youtube.com/watch?v=BI2Uf3T75Cg