It is an interesting article, but not really a Show HN because there is nothing I can play with or try out...unless you ship me an old compatible Mac... my email is in my profile :

...I'll admit I wasn't entirely sure if this could be a Show HN or not, I might have chosen wrong!

However, the guide includes a ton of software I made, which can absolutely be tried out—Aqua Proxy, updated QuickTime components, SIMBL plugins, etc—by anyone with compatible hardware.

I'm sorry you don't have the right hardware. :( You could use a virtual machine but there's really no point. But I don't think this in itself should disqualify a Show HN submission, right? Otherwise, the only thing people could submit would be webapps!