I think you are right, stuff from the PSN is usually assigned to a specific console upon installing. You can still find the data and move it, but probably get an error code when trying to launch it if you can enable access to it.
However, it is possible to create a program that decrypts it and encrypt it to fit your needs.
Edit:
I just had a thought process:
Would it be possible to download the same content on two different PS3's, take both encrypted files, compare them, the whole coding for the DLC should be the same, what should be different is the arbitrary string that ties it into a console. It may be possible to edit that arbitrary string to the one on your console. Edit the PS3 menu to enable access to your new content and viola?
Second Edit:
It may not even be console specific? Maybe as long as you have it in appropriate directories, games that use it will be able to find it. So many questions and I only have one PS3 with no Network access.... fuck