My understanding of Magento is that you can only have 2 themes loaded at any one time. ( according to the Magento design guide)
Also, that there is two types of themes - default and non-default (i.e. default contain all possible options, non-default override a subset).
All the documentation I've read says that both default and non-default themes are set in the configuration-> section. I don't see how I can have a customised default theme (not called default) and non-default theme at the same time. Do I have to rename my theme to default in order to use non-default themes?