As an example, the responsible individuals of Mt.Gox would need to come up with a repayment plan for every single penny/bitcoin that they still owe. The fact that it was "stolen" from them is irrelevant, as the users entrusted the safekeeping of their money/bitcoin to MtGox. If that means that they will continually have X% of their yearly incomes divied up amongst the users, then so be it. And this will continue indefinitely until the debt has been repaid.
Sadly, this sort of solution to the problem would never be instituted in our society. Precisely because it exposes flaws in our concept of the relation between debt and slavery. In essence, it would put the individuals responsible for the fraud in a sort of indentured servitude until the debt has been settled.
It does sound like quite a scary proposition, I'll be honest. As it's something completely alien to what we're accustomed to when it comes to debt/bankruptcy. But I assure you, if this were ever instituted, and a few individuals got bitten by it: Society as a whole will grow in a much safer direction, both with more security precautions when debt is involved, and with insurance to cover losses such as this. All that, without state intervention/bailout.