Ah....that would hinder the process slightly.
I downloaded the required patch files directly from My Oracle Support using the support access i have with my current client.
I have a 12.1.1 Vision install and have successfully patched it up to 12.1.3, although I did take a leap of faith when executing parts of it. I followed the steps included in the readme files with the patchset.
12.1.3 does not come with an auto install release, hence there is no instant vision install. To get there you have to go via the patching / upgrade route.
For 12.0.4 i think you would need a slightly different patchset to the one i used (presumably to get from 12.0.4 to 12.1.1 etc).
Of course the next big thing to look out for will be the "Vision" version for Fusion Apps

Although i wonder whether this would actually run on a laptop