With Lehman and Merrill gone, two independent investment banking firms remain:  Goldman and Morgan.  Which will be next for rumors and expressions of concern from the market?  Morgan Stanley, most likely.  But in either event, both may well have a tough time of things.  As the WSJ notes: 

• The firms live or die by market confidence, given their reliance on wholesale funding, and that has clearly evaporated for the smaller firms. The lure of more stable balance-sheet funding will be strong even for Goldman and Morgan Stanley. The question is who would they partner with? There isn't a long list of banks big enough to step up.

• Even if Goldman and Morgan Stanley dodge the immediate danger, they need to lock in a funding model that is not susceptible to a sudden loss of confidence. Otherwise, they remain at the mercy of the market.

In other words, the outcome is inevitable.  Either they will suffer the fate of Lehman/Merrill or will need to partner with someone that will provide the market will additional confidence and allow them to survive periods of market instability.  Who will this be?  Commercial banks, of course.