It might even be possible to use the real server for this. There's something in the source called INDENT_VERSION that says change this if you're not Simon, and when I changed it, I got brought to a server with only a few amount of saves on it, and I think all saves made from that version would appear on that small list. I'm not sure though, it didn't appear to work right, because it only shows about 10 random saves from the whole server. Maybe if it was fixed, if that was the purpose, then it could be used to do this without needing to create a server.
Something I find strange is that even though the powder toy website is blocked at my school, I can still get to all the saves online and update it. Minecraft is the same way, I updated it at school once.
@Minishooz(View Post) I didn't do anything, they just only blocked the website part at my school, not the save server. The powder toy can use proxys, maybe you could try doing that (see the README for more info on how, you need to create a shortcut). To get the powder toy on my computer, I just emailed it to myself.