I was running the Gore-at-the-convention fantasy for a long while now but the speaker sequence (along w/ the texting and the timing) has convinced me that's less likely: if it is Gore, I think you want that fact settled before the Hill-and-Bill show, because it will significantly affect how they position themselves in relation to the ticket and the party, and how their supporters behave at the convention, roll call, etc.  Schadenfreude lovers might dwell for a moment on the vision of lots of Clinton nostalgia/buyer's remorse suddenly and embarrassingly crushed into oblivion by the far more powerful effect of Gore on the ticket, but I don't think that's a likely or helpful scene at the convention.  The reason these two got their 2 nights and their roll call, I think, is that after the VP announcement these are just big showcases of Obama's power to unite the party, Clintons included, at length, on 2 nights.  We won't hear a word about party unity after the announcement, and recalcitrant Clintonism will be a sideshow--the smart ones will know that, and avoid it.

I know there are other scenarios, but they don't do or explain as much--see for example the confidence of our nominee in CA last night.