I'm enjoying the speculation about which Senators wind up chairing which committees as much as anyone (the best yet is this chart from the New Republic), but a little perspective would be nice here: it doesn't matter very much. This is more or less on par with the transition-season frenzy about who gets the various cabinet offices; "opening needs to be filled" is a great journalism story because it has a clear plot and promises to have a clear conclusion.
This particular story is more on a par with "who will be Secretary of Commerce" than "who will be Secretary of Defense." It just doesn't matter a lot. That's because committees in the Senate aren't nearly as important as committees in the House, which is because Senators, as the saying goes, retain their rights. Members of the House are willing to trade their very small (1/435) influence over most issues in order to have a lot of influence over a small number of issues. Senators, because their districts contain more interests and because the need for a division of labor isn't as great in the smaller body, are not willing to make that trade. That's not to say that committees are entirely irrelevant in the Senate, but only that their influence is modest. It might matter a lot that Henry Waxman, and not John Dingell, is chair of Energy and Commerce; if a bill is bottled up in the House, it is as good as dead in most cases, and a chair (working with party leadership) can control what happens to a bill once it does reach the floor of the House. That's not true in the Senate.
If a uncompromising liberal had been chair of Senate Finance instead of Max Baucus, there's a good chance that a bill would have been reported out long ago...only to face negotiations before the bill reached the floor of the Senate, negotiations arranged on terms dictated by marginal Democrats such as Baucus. Again, that doesn't mean the chair is irrelevant; Baucus certainly had a lot of options available for how to run his negotiations. But given the natural goal of marginal Democrats to find some cover for a liberal vote in an atmosphere in which minority party votes are not available, odds are that something similar to the current roadblock would have taken place at some point before Senate passage. The details of how it's happening are consequences of the particular personalities involved in particular committees; that it's happening at all is a consequence of the structure of the Senate and the mathematics of liberal Democrats, marginal Democrats, marginal Republicans, and rejectionist Republicans.