The view of Gringotts not as vaults in a bank, but a massive mausoleum is irresistible. It puts a lot of wizard-goblin history in a different light. In a way they aren't asking for their treasures back, but for their history to be respected.
I've often wondered about Filius' background and how it might have affected him. For example, his canon proficiency at duelling as a Professor makes perfect sense if you view him as a tiny young, bullied boy. In the same way his reticence to open up here and his embarrassment at Griphook spilling his secret could well have roots in the ancient laws governing wizards vs. those of "near-human" ancestry. Might he not have been allowed to even attend Hogwarts if he (& his family?) hadn't kept it hidden?
Like all good stories this one leaves one wondering this and so much more... even to Filius' sexual habits and if he's ever been truly satisfied by his intervening partners (if any) or happy in a nonacademic sense. Food for thought! What I like most about hp_beholder. Nicely accomplished! Oh, and I love how you present Neville here. :-)