At this point, the writing is on the wall. Hillary Clinton ran a good campaign but at this point there are to many assumptions built into any math that the Clinton camp is using. And the most likely chance she has of becoming president is now furthered by the suspension of her campaign.
Here is what would need to happen in order for Clinton to win the presidency:
In order to believe that she can win the presidency, her campaign would have to assume that a coup by the super delegates would leave her a viable candidate. For all of their on air ramblings, neither Clinton nor her supporters can actually believe that a credentials fight will not be an enormous handicap going into the general election.
Second, she has to believe that she can actually prevail if she takes her fight to the Rules Committee. Granted the membership of the committee currently favors her, but it is important to remember that the committee members are first and foremost party activists. Even if her campaign believes an attempted coup would not do serious damage to the party, it seems unlikely that 50% of the committee does.
Third, she has to believe that when they are challenged at the Credentials Committee, she will retain her supporters and be able to convince enough Obama and/or Dean appointees to vote with her.
But fine, lets say that the Clinton camp believes this is an actual possibility. So now we have delegate totals of:
Obama- 1,911.5
Clinton- 1,1874
Edwards-32
Undeclared-56
Out of 2208.5 required.
And let's say that she manages to win over 2/3 of Edwards supporters and that 1/3 of the Uncommitteds are Edwards backers.
O- 1964
C-1923
Why don't we also say does astoundingly well in the upcoming contests. 65 % in her states, 50% in his:
O-2,049
C-2,060
Assuming this astoundingly unlikely set of presumptions she also still has to hold of her pledged delegates (who don't forget, can always break ranks and are party activists themselves) and all of her supers. And pick up 45% of the outstanding superdelegates.
There is one other course to the nomination. Barak Obama could die or otherwise seriously injured or a scandal (and at this point we're talking dead girl or live boy) could render him unelectable. In either case, Hillary Clinton's path to the presidency is a lot easier if she suspends her campaign now. If Barak is forced to drop out, she has a more unified party and if a scandal or some-serious-but-not-life threatening medical condition arises, she will have more of her people in place (and less ill will) if there is a convention fight. Since the above conditions could only be hoped to take place in some sort of bizarre twist anyway, her interests (in terms of the presidency at least) are better served by withdrawing.
[By the way, my numbers might be off a bit due to rounding].