What I would do for each database is:
- Create a VM.
- Install the OS on the VM.
- Install Oracle on top if the host in the VM.
- Create a database using DBCA with the same name/sid.
When you want to do the switch:
- Shut down both databases (original and VM one).
- Delete the controlfiles, datafiles, tempfiles, redo logs etc. from the VM.
- Copy the files from the original machine to the VM.
- Start the DB on the VM.
- If the positions of the files have changed (directory paths not the same) rename them. (http://www.oracle-base.com/articles/mis ... -files.php
That's about it for a quick outline.