The more I think about this the stranger it seems. The war chest was five million pounds? Apparently Dumbledore doesn't have any rich Muggle friends who'd be willing to spot him a loan on that whole 'saving all Britain from a super-powered psychopath' thing.

It's not like the DMLE is all-powerful or anything, Moody thinks that the Eye of Vance was "currently in the possession of a powerful Dark Wizard ruling over some tiny forgotten hellhole that wasn't in Britain or anywhere else he'd have to worry about silly rules." What's stopping any enterprising wizard from knocking over an African diamond mine?

And while yes, Harry's debt is almost certainly going to be made irrelevant long before it comes due, the fact remains that one of the most powerful wizards in the world considered five million pounds to be really serious money. I'm kind of interested if (how) the story will address each and every possible moneymaking scheme and present reasons why Dumbledore couldn't do them.