A madame Maxime realmente tinha ossos grandes?

Como o Hagrid, ela tem sangue gigante.

Da entrada de Pottermore para a "Academia de Magia de Beauxbatons":

Headmistress Olympe Maxime is (in spite of her protestations to the contrary) half-giantess; brilliant, elegant and undeniably awe-inspiring.

Alternativamente, esta questão foi sugerida de forma indireta em uma entrevista Relíquias da Morte

Did Hagrid ever get married and have children?

No. […] No, no, Hagrid never did marry and have children. […] Realistically, Hagrid’s pool of potential girlfriends is extremely limited. Because with the giants killing each other off, the number of giantesses around is infinitesimal and he met one of the only ones, and I’m afraid, she thought he was kind of cute, but she was a little more, how should I put it, sophisticated than Hagrid.

— J.K. Rowling at Carnegie Hall, October 2007

Esta passagem deve estar se referindo a Madame Maxime, e assim deduzimos que ela é giganta (embora ao contrário de Pottermore, isso não confirma que ela é metade -gigiosa)

Embora nunca mencionado explicitamente, somos levados a acreditar que Madame Maxine é na verdade meio-gigante.

Este é um truque, já que tudo o que temos (dos livros) é o ponto de vista de Harry; e Harry só ouve alusões a este assunto, e principalmente de passagem.

Mas pelo que ele ouve, ele definitivamente conclui que ela deve ser meio gigante:

“I don’t know who Maxime thinks she’s kidding,” Harry said, watching Madame Maxime sitting alone at the judges’ table, looking very somber. “If Hagrid’s half-giant, she definitely is. Big bones . . . the only thing that’s got bigger bones than her is a dinosaur.”
^{-Harry Potter and the Goblet of Fire, Chapter Twenty-Three (The Yule Ball).}

Dadas as evidências, e a reação de Madame Maxine a Hagrid trazendo o assunto para cima, também podemos chegar com segurança à mesma conclusão:

“Eh?” said Hagrid blankly. “No, don’ go! I’ve — I’ve never met another one before!”
“Anuzzer what, precisely?” said Madame Maxime, her tone icy.
Harry could have told Hagrid it was best not to answer; he stood there in the shadows gritting his teeth, hoping against hope he wouldn’t — but it was no good.
“Another half-giant, o’ course!” said Hagrid.
“ ’Ow dare you!” shrieked Madame Maxime. Her voice exploded through the peaceful night air like a foghorn; behind him, Harry heard Fleur and Roger fall out of their rosebush. “I ’ave nevair been more insulted in my life! ’Alf-giant? Moi? I ’ave — I ’ave big bones!”
^{-Harry Potter and the Goblet of Fire, Chapter Twenty-Three (The Yule Ball).}

Desculpe por ressuscitar isso.

Eu vou dizer que a resposta é um claro não. Ela não tinha apenas ossos grandes, ela era meio-gigante.

Em O Cálice de Fogo , depois que Harry tem sua visão, ele vai ver o Professor Dumbledore e ouve ele e Fudge falando sobre a morte de Barton Crouch:

'Or else - well ...' Fudge sounded embarrassed. 'Well, I'll reserve judgement until after I've seen the place where he was found, but you say it was just past the Beauxbatons carriage? Dumbledore, you know what that woman is?'

'I consider her to be a very able Headmistress - and an excellent dancer,' said Dumbledore quietly.

'Dumbledore, come!' said Fudge angrily. 'Don't you think you might be prejudiced in her favour because of Hagrid? They don't all turn out harmless - if, indeed, you can call Hagrid harmless, with that monster fixation he's got -'

'I no more suspect Madame Maxime than Hagrid,' said Dumbledore, just as calmly. 'I think it possible that it is you who are prejudiced, Cornelius.'

Harry Potter and the Goblet of Fire - p.503 - Bloomsbury - chapter 29, The Dream