I post this partly because this demonstrates the willingness of the Vietnamese to share anything and partly because I think this is a fun photo.
You actually see this quite often with everything from this type of configuration through to moto-assisted Cyclos.
In fact if you revisit the "ice man" picture that received so much comment previously, you will note a motobike wheel peeking out to the left of the ice block. Moto-assisted ice cart!