If you ever need to run multiple Magento configurations from the same copy of core files, this wiki article will help you with basic configuration.
I’ve used it to create QA and demo copies, for easy upgrade of both Magento and tested/demoed extensions.
Let me know if it was useful for you!

Would this allow you to have different templates/ configuration also?
I am guessing yes, but not sure.
Hi James,
This method is used to have different configurations / databases, using the same Magento code copy.
Yes, you could have different templates as well, but this method is not required for that, as you could have different themes within the same Magento database/configuration.
Unless I didn’t understand the question
I am considering using this method so I can setup an number of magneto websites, each with their own database/configuration and separate administrative access by the store owners. But I dont want it to be a nightmare to upgrade the software.
Unless you have a plugin that enables Advanced Administrator Roles and Permission Restriction per Site (Website and Store View) without it costing $12k annually like the Magento Enterprise version does.
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