It was standing room only today in one Capitol hearing room, but the man sitting in the middle of the dais wasn’t someone you would recognize… and probably is someone you haven’t heard of.

His name is Jon Gruber, a researcher from M.I.T. And for the rest of the year, every time you hear someone quote the price tag of a major health care reform proposal… chances are that he came up with the number.

Gruber, who just completed a cost and coverage analysis of the two bills written by Assembly Speaker Fabian Nunez and Senate President pro Tem Don Perata, traveled to Sacramento today to explain his research.

He’s also the one who earlier this year pegged the cost of Governor Schwarzenegger’s reform idea at $12 billion, a plan which was never introduced as legislation. And as mentioned yesterday, he has now pegged the cost of the Nunez plan at $8.3 billion, and the Perata plan at $10.9 billion.

The roughly 90 minute presentation this morning was deep– too deep, perhaps into health care wonkdom for a blog posting. But a few items are worth pondering.

Gruber believes the governor’s suggested plan would cover all but about 800,000 of the uninsured, while both Democratic leaders’ plans would cover all but about 1.5 million of the uninsured.

Speaking of the uninsured in California… Gruber says that about 1.2 million of the 4.9 million without coverage are undocumented immigrants. But of those immigrants, he estimates only about 100,000 are kids. Remember that number when the debate over health care for all kids, regardless of immigration status, heats back up this year.

You can click here to listen to Gruber explain where all of the uninsured end up under the governor’s framework (interestingly, he says there would be no net change in how many are covered by employer-provided health care). And, for comparison, click here to listen to Gruber explain what happens to the uninsured under the Nunez and Perata plans.

Gruber’s complete presentation is supposed to be online here later today. Yes, this is weighty stuff to get through. But as everyone agrees, now the real negotiations will begin.