NOSTALGIA ALERT! There is now an honest-to-goodness Retro MacOS emulator for jailbroken iPhones in the form of Mini vMac, which loads disk images and everything. It's like getting your first Mac all over again.
The OS, developed by Named Fork, is based around that found on the Mac Plus (v3.0, presumably). If you can stomach the god-awful nu-metal soundtrack (or whatever they're calling it these days), the video runs through a demo of the different control schemes for using the OS with a touchscreen.
Admittedly, it looks like more work than it probably is, especially since you have to track down and convert the retro software yourself (more info here). But if I can play some Number Crunchers, and maybe a little Lode Runner, I'd gladly suffer some tedium to revisit my childhood technological awakening. [Named Fork via Nowhere Else via CrunchGear]
Also check out more images at Nowhere Else