Apple used to provide the 400k version on their ftp site, it was 4 disks I think, now all they provide are the 800k. I've always wanted to try System 6 on a Macintosh (128k), I've heard it works, now I have a 128k and am forced to use System 4.
Too bad Apple recently stopped letting user groups distribute old system software, Mac512 was the only place where I could ever find system software prior to System 6. Great move, Apple (Legal), you not only stop supporting old macs, you cut the only sources of software for them. These computers are almost 20 years old, it's not like anyone's ripping Apple off by distributing software necessary for them to run.
If anyone knows a site where I can find pre System 6 system software, I want to download all of them,maybe I'll mirror them some day

I seem to remember a Hotline server having them. btw, anyone out there still developing any software that runs in 6?