Have you looked through the
Script Listings?
Have you used the
search function?
Given the rarity of an ABS, you are more than likely going to find all this site has to offer in one of those two places. If you cannot find one that has all the scripts posted, you are out of luck.
The reason why most ABS scripts have demos is because they are very large scripts. They involve book-length code that is a pain in the butt to post. Not to mention the instructions are very indepth and really do best with examples. Some ABS topics out there have instructions in the post as well, and you might be able to find one with a document of the script you can save.
Your best bet is just to ask permission to download one thing. They are usually not that big of a file, and you can always run a virus check.
Hope this helped.