As we have seen on this thread, there are many ways of reading the
Baluchistan mention.
There are other possibilities than just Manmohan Singh becoming a victim of sudden burst of Jhappi-Puppy Emotionality. There are also good reasons why others were not confided with on this.
n+1st Theory - Ego-Spot Shift Theory
Americans derive their leverage in Pakistan from the role they can play there as pro-Pakistanis umpires viz-a-viz India. Every time some Gora comes along and says a few words in favor of Pakistani position on Kashmir, the Pakistanis go gaga, and are willing to give away their favorite Ayesha goat in return. Pakistanis are simply suckers for it. Not only that, the Pakistanis want the Goras to confirm that their position is right viz-a-viz India on any other sticking issue. Usually it is a sign of weakness to want confirmation from others.
Now the problem has always been that all issues that are disputed in Indo-Pak relations are of ultra-sensitivity to India as well - most predominantly the Kashmir issue. India is justified to be sensitive about the issue. So whenever an American or a Brit make a remark on Kashmir simply to massage the big Pakistani ego, so that the Pakistanis deliver some xyz to America or Britain, they inadvertently step on India's toes as well.
Some here may think differently and they may be right too, but my reading is that after Kargil, the West has practically accepted the LoC as the international border between India and Pakistan. That understanding was reached in the time of Bill Clinton itself. After 9/11, nobody in their right minds in the West, would like to concede more ground to the Islamists anyway. Bush did not even see it fit to get involved in the whole thing, so he kept his distance from Kashmir. So I consider the question, whether India can hold on to Kashmir or not or through magic is forced to sign away our part of Kashmir away or something, to be a moot question. There is no possibility of that. The reason, why I think, there is far less desire in the West to needle India on Kashmir, is simply because the West accepts countries which fulfill one criteria - support them in upholding the various global institutions and power structures established by them. That is why they look upon India somewhat more benignly. The EJ issue is a separate issue.
But if they put away Kashmir, as they might well like to put away, the Anglo-Americans lose a vital Pakistani ego spot to massage. So another ego-spot may be the need of the hour. A different field where they can play their ego-massage games on Pakistan. That is where Baluchistan may be right ego-spot at the right place at the right time. Baluchistan does not constitute (though in my opinion it should) a vital Indian interest, so American umpire-ship there would not hurt any core Indian interest and at the same time Pakistan can be caressed.
The focus of interest and attention shifts from a place within India to a place outside India. The Americans can 'force' Indians to go on the defensive in a place outside India, which is not of our vital interest. True to such a reading of the matter, Kashmir was not even mentioned once in the Joint Statement.
n+2nd Theory - Blackmail Theory
Being a 'friend' of Pakistan, America cannot get itself involved in the various insurgencies in Pakistan and call them by their name - freedom struggle of the Baluchis, or Pushtuns, etc.
It cannot make any supportive statements on Baluchistan freedom struggle either, as then the Pakistanis would look upon America as the culprit, as an enemy of Pakistan, and all US-Pak cooperation on the war on Al-Qaeda would come to an abrupt end. So America chooses to take on the role not of the foe but rather of the mediator. Now mediation is a great thing. Both parties run to you to get your support and are willing to bend over even. Since Baluchistan is not a core Indian interest, it is basically the Pakis who would be pleading with USA to support the Pakistanis perspective, and that as more and more information on Baluchistan, and Pakistani atrocities, is made available through the international press.
That gives the Americans a lever. The Pakistanis would be mortified that their basis of control over Baluchistan would be disputed, just as Indians get worked up, when Kashmir's accession to India is disputed.
That gives the Americans a new leverage to force the Pakistanis to behave and cooperate.
n+3rd Theory - The Subversion Theory
It can also be that the Americans feel that the situation in Pakistan is now ripe for the next stage of its development. It is time for Baluchistan to be separated from Pakistan. After all Baluchistan is really a great piece of real estate sitting there on the Arabian Sea with borders with Iran and Afghanistan and further access to Central Asia.
There will be now a whole host of Baloch leaders being given prominence around the world, who will be commenting on various levels of freedom and independence.
An Article from 14.05.2008 -
Unveiling the hidden players in Balochistan by Hamid Waheed: Frontier Post
Recent Activities of Mir Suleiman, Khan of Kalat operating from U.K, holding international rallies and submitting letter to 10, Downing Street projecting forcible annexation of Balochistan by Pakistan?
As such the Baluchistan mention in the Joint Statement could be the simply to get a new wedge into the whole internationalization of Baluchistan issue sponsored by America and Britain with India simply playing along.
n+4th Theory - Equal-Equal for Deescalation
Up till now most criticism directed towards MMS has been that now Pakistan can do an equal-equal on terrorism, and can justify terrorism in Kashmir based on alleged Indian involvement in supporting the Baluchistani insurgency.
But this works the other way also - where India and Pakistan agree that if Pakistan deescalates its Pakistan-sponsored terrorism in India including in Kashmir, India may be willing to withhold substantial support to the Baluchis. If Pakistan deescalates, India deescalates. We can force Pakistan to stop terrorism directed at India by extortion, by offering the option of stopping support for Baluchi forces, otherwise increasing it accordingly.
It would be helpful if the Baluchi struggle for Independence is not adjudged as Islamic terrorism in the world media.
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All the above theories can be wrong. Only time will tell how the cookie crumbles. It will be too early comprehend the Baluchistan mention in the Joint Statement from Sharm-el-Sheikh.
, the issue because of which it cannot cooperate in the US GOAT fully 
and blah blah 
. That is why you see it mentioned so much in the international media - because it affects American plans. Has India ever raised the issue of Baloch people being massacred on any international forum? it is never too late though. Now is the time. 
of Balochistan (I mean Pardestan) and Pakhtoonistan and Balwaristan and Sindhudesh, that they absolutely INSIST on putting their panic in every statement they write. 
at such proposals.
Amazing U turn, and this is not because they too want to hang hafeez sayeed. 