have you considered asking WHY the weak banks are weak?
were the weak banks the ones coluding to inflate home values in order to have larger morgage notes to bundle and sell on the markets?
were the weak banks spending more money on lobbyists rather than depositors?
were the weak banks issuing credit cards like candy to high risk people?
Maybe the weak banks brought their problems on themselves, but their collapse will take any number of sound banks that did not take part in the shady practices with them. In the end, all will suffer. IMO this thing is too big to be explained entirely by bad loans, etc.