While I agree that Gadaffi must certainly have had a significant degree of support, and also that the various armed groups of rebels are currently fragmented along tribal and ethnic lines, I think that this view can be pushed to far.
To see this as simply an East vs West civil war is to ignore the very definite large-scale support the rebels have received in and around Tripoli. The TNC in Benghazi have been adamant that they fight for the freedom of all Libyans, not for secession or to settle old scores - and while the fact that they need to say it indicates there are fault lines there, there has been nothing really credible to say that they are a) not sincere or b) being rejected on these grounds.
Tribes obviously play a part, especially in rural areas, but Libya is plainly not simply a tribal society - intermarriage is common in the big cities, and this is where the initial uprisings happened. There is a nation of Libya, on top of the other regional, ethnic and tribal identities. This was what initially took to the streets against Gadaffi at the beginning - it wasn't dispossessed tribes, or rebellious Easterners, it was the young people of Libya inspired by events in neighbouring countries.
Building a new society in Libya is a massive challenge, and there are huge potential problems, but I doubt it is as impossible a task as some think. The basic building blocks are there, and the desire from a large segment of the population. Massive oil wealth isn't a bad thing either, since the new government will actually be able to satisfy some of the key economic demands, unlike in say Egypt or Tunisia.