The is canon evidence of this. Snape=Doe= Lily, Tonks=Immense four-legged creature (possible a wolf, IMO)= Remus.
Originally posted by Cheslea
Remember, too, that while a person's Animagus form tends to represent their own nature, their Patronus might represent something that protects them or is important to them - for example, Hermione has an otter (related to the weasel and therefore a link to Ron) and Harry has a stag because that was his Dad's Animagus form. So perhaps Fleur's Patronus could be something linked to Bill?