For what it is worth, in 1982 there was a standoff on raising the debt ceiling. President Reagan initiated a “very confidential planning exercise” to prioritize spending. Details as to priorities were not disclosed, so as to maximize the Administration's leverage.
My guess is that if a contingency plan were outlined, then the battle would shift not to the extent and path to debt reduction in exchange for a debt ceiling hike, but to a battle over spending priorities in the contingency plan. At the same time, knowledge of such details would reduce the incentive to reach an agreement to avert a possible default/wrenching spending choices.
At the same time, I don't believe the Republicans should give away their bottom line too easily. If, for example, they have no intention of dragging things beyond August 2, even if no agreement on significant spending reductions is achieved, they should not disclose that. Otherwise, they will lock themselves into a situation where they will gain much less than might otherwise have been the case.
In any case, I still believe some kind of agreement is more likely than no agreement. I also suspect that the really tough choices will be postponed in favor of goals for which policy specifics have yet to be devised. Somewhat broad language will likely also be used e.g., there might be agreement that tax reform would be examined in the future. Republicans would continue to assert that the deal did not raise taxes. Democrats would assert that the language does not fully preclude revenue-enhancing measures. But the exact specifics that would clarify what would be deliberate ambiguity would be left to be resolved after the 2012 election.
Finally, I do believe the Republican request provides some possible insight into the Republican position. It could reflect the possibility that the Republican Leadership is concerned that a significant base of Republicans may not accept the likely parameters of a deal, hence they want to become better informed as to alternatives. It could also be a ploy to maximize leverage by making it appear that the Republicans are serious that they won't accept a deal they don't believe is adequate. Indeed, one should not be too surprised if some prominent Republicans announce that they are leaning against approving a debt ceiling increase in the weeks ahead to step up the pressure on the White House. My guess is that there is a combination of both factors at play. Of course, serious risks are involved. If the financial markets begin to expect a realistic risk of an impasse, things could begin to get out of hand.