Unocal has a consistant company policy of saying they will do buisness with all existing regimes, and that the United States should recognise all existing regimes. The theory behind this is that the benefits both to Unocal and the native population of trade and development outweigh the harm done by recognising a bad regime which would be in power anyway. This of course has earned Unocal much criticism from liberal human rights groups both in Burma/Myamar and in Afghanistan. In order for your conspiracy theory to be true, Unocal would have to be engineering conflict to bring about the overthrow of the government of Afghanistan, which is against company policy.
This multiple pipelines theory won't fly either. In order for a pipeline to be profitable there has to be a certain minimum volume of oil or gas flowing through it in order to offset the cost of construction and maintenace. This is why, for example, the oil industry needs to drill in the 10-02 area of the ANWR in Alaska since the amount of oil produced by existing fields is gradually diminishing. Your argument is like saying that I am going to open eight new supermarkets in the same town and they are all going to be profitable.