Body parts modeling is not this which you illustrated. That's still a regular model.
Body Parts Modeling is just one part (not the whole body) and each model specializes in only one body part. Hands, legs and feet are the most common.
She will need to have an exceptionally attracive body part (whatever her specialy is) and will have to make sure that part stays perfect and well groomed at all times. I've heard of hand models who wear gloves all the time they are not working, to prevent tanning, age spots and wrinkles, not to mention having perfectly manicured nails all the time (without nail polish, because that can stain them).
Most of this kind of work is "commercial" (for ads of things like jewelry, but also bath products, food, computers, shoes, nail polish, medical/insurance, sports equipment ... anywhere a person's hand, foot or leg would be needed) so a good commercial agency or talent agency would be a place to start to inquire if they have a need for body parts modeling. I can't offer names of agencies that rep parts models ... sorry.