Bloomberg may endorse Obama

First Bill Richardson, now former Republican and current Mayor of New York Michael Bloomberg.  Some have been speculating that the Obama campaign would unveil a wave of high-profile endorsements leading up to the Pennsylvania primary in an effort to push the electability factor and generate added momentum:

Mayor Michael Bloomberg will stand side by side with Democraticpresidential hopeful Sen Barack Obama for the second time in fourmonths Thursday. Bloomberg will introduce the Illinois senator at aspeech on the economy at Cooper Union College.

There may be more to come as well.  Al Gore?  John Edwards?

Also, this might make certain that Bloomberg isn't running for president himself.  Could Obama be considering him as a running mate?