It's very simple. Whatever amazing plan either senator has is probably well-known to leading members on those committees. Obama can talk to all the former SEC chairmen and treasury secretaries he wants to formulate his plan, but in all likelihood members of Congress have already done this.
You don't need to be in Washington to offer input or discuss a plan to resolve the issue unless they are serving in their official capacity as senators. Their presence there will likely polarize parties. I mean, think about it... if Obama suggests something brilliant but controversial, will Republican lawmakers be more or less inclined to support it? How about if McCain offers the same? Will Democrats be more or less inclined to support it?
We can make calls for bipartisanship all we want, but at the end of the day, this is a presidential election season. Everything is political, and I hope that truly worthy ideas aren't lost in the mix because of it.
-- Todd/Leviathn