Even though there's apparently no 'official' dvd-rom contents for Empire, that hasn't stopped Starkiller from creating some to make all three releases consistent:

Posted by............: The Starkiller
Posted to............: alt.binaries.starwars

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It is my understanding that the EditDroid DVD offering of The Empire Strikes
Back did not feature DVD-ROM content. However, Star Wars and Return of the Jedi
both did. So, for the sake of continuity, I have created a DVD-ROM CONTENT
folder to complement the ESB DVD.

This CONTENT folder features images and content of The Empire Strikes Back
Portfolio by Ralph McQuarrie and original scripts in PDF format. The
high-res images aren't the best, but they are the best I had available.

I would like to thank the members of EditDroid for creating this most excellent
set of DVDs. I hope they don't mind my small addition.

Again, I hope Starkiller doesn't object to me nicking his post and putting it here, and thanks once more for making and sharing it in the first place:
Click here to download it from Rapidshare