^ They posted systems going all the way back. Its where I made my first archive from back in the 90s. I think the directory was even called "older system". They also stored all the Newton releases there. In fact, there is still stuff there.
To expand on Paralel's post, anything from 7 Pro up is a no-no to post technically. Excluding updates which are not full systems. But I am not sure if that is true anymore since Apple themselves has 7.5.3 as a complete download right not. And I am not sure what else is out there since I have not poked around the server yet, but there is more. So Apple may have abandoned System 7. Maybe even 8 (which I doubt).
A link to 7.0, I guess smaller disk images are inside this single download. But I have not checked.
http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English -North_American/Macintosh/System/Older_System/System_7.0.x/System_7.0.smi.bin