There is interesting discussion on Paul Krugman's NYT blog today regarding monetary expansion and the Great Depression. For the current crisis, I think you need to look at the divergence of M2 and M3. As institutional money market investors fund commercial paper that funds asset sales by originators, M2 is converted to M3. The money multiplier becomes unlimited as the original reserves used to fund loans are returned in full to the banking system with no new net increase in deposit liabilities. What's happening right now is the reverse – M3 is liquidating and the monetary base is expanding to, in part, accommodate the conversion. If you look at Institutional Money Market Funds on Z.1 you will see the reductions in this (and, I believe other) components of M3 relating to credit expansion in the modern financial system. I have been waiting for the next Z.1 to confirm these movements.
I believe M3 is important, notwithstanding the Fed's decision to stop publishing it. I have not concluded that the M3 expansion is the cause of the bubble, but it certainly shows how monetary expansion and, in particular credit expansion, contributed. I plan to post more on this after the holiday weekend.