Bazza, you describe a typical market situation. If the costs associated with transport of produce get higher, produce transported a short distance becomes economically more attractive. This is how markets typically work.

Unfortunately, at the moment transport is a fairly small component of current costs, with labour and other factors making up a much larger component.

Energy use is already factored into the costs. Doing a full energy budget may show that one strategy uses more energy than another, but while energy is cheaper than labour, labour costs will dominate the costs. To change this, energy will have to become more expensive than labour, or a tax (such as a carbon tax) will need to be introduced in order to change behaviour. One of the problems with taxes (or indeed subsidies) where the tax is not representative of the value of the service is that they end up distorting markets