Can Sudan Really be One Nation?

Sudan is the largest nation in Africa. It shares the difficulty most African nations have in that the borders as far as ethnicity are concerned do not represent reality. I am guessing if it were not for the Egyptian and the British push Southward in the 19th Century, it would not be one nation now.

I am not an economist, but I am curious as to what would be economically realistic borders. Would the rest of the world be willing to help Sudan develop? Again, should it be one nation?

The Northern boundary is roughly at the Tropic of Cancer and Wadi Halfa. Having said that, is that a "natural" border with Egypt?

The West, well Chad has the same type of land as Darfur. The East is more obvious. The Red Sea and Ethiopia. The South, well... again those ethnic groups cross the "national" borders.

I am just asking questions here to make people think. I admit freely I do not have a solution.