Gaddafi is not going to give up without a fight. He is using African mercenaries and all of the military assets at his disposal (fighter jets, anti-aircraft guns, apparently naval vessels moored off Tripoli) along with his thuggish militias in order to hold on to Tripoli and parts of the West. The East has fallen to anti-Gaddafi protesters and to date he doesn’t seem to have made significant efforts to retake that portion of the country.
The difficulty for Gaddafi is that even if he is able to hold on to some segment of the country around Tripoli, he is finished economically. Even the most die-hard sanctions buster won’t do business with him now that he has used these types of heavy weapons against unarmed demonstrators. The Western nations won’t help him; paradoxically because he is weak now they will wait out his downfall and do business with his successor (or many successors, if the nation splits up) rather than paying the immense public relations price of working with a dictator with so much blood on his hands.
It is interesting that people assume that the borders are inviolate. As it has been noted many times the borders of Africa that the colonial nations agreed upon do not necessarily make sense; but for many reasons it hasn’t made sense to attempt to re-map them along different lines. The one recent exception is South Darfur and this could prove contagious.
It is not out of the realm of possibility that Egypt would attempt to take dominion over the oil rich provinces of the Eastern half of the country. There are many affinities between tribes in adjacent areas along their border. This could be done under the guise of a humanitarian mission if Gaddafi attempts to re-take the East; the Egyptian army could intervene (and would swat away Gaddafi’s militias) and then de-facto control the East under the “boots on the ground” theory. While no one knows for certain it seems that there are > 500,000 Egyptians on the ground in Libya; I don’t know about ANY of these numbers because I have heard that many Africans from neighboring countries are also there but when you add up all of these non Libyan residents it seems like an impossibly large proportion of the population.
Given that no one expected Libya to fall in the first place and that Libya seems to be a nation with little civil society and cooperation between regions it could just splinters into multiple, smaller states each tethered to their respective oil wealth. Ironically the disappearance of Gaddafi could re-invigorate the oil industry which had been crippled by sanctions until ENI (Italy oil major) came in and basically signed deals with him to bring more capacity on line.