"I want it to be as fast as possible.
Most importantly, I need it to not need shutting down."
A cheap dedicated print server would be the obvious answer:
Minute power consumption
Much faster than a printer can handle
Free up a proper PC for something more interesting
It just works
"I would if I could" is what comes to mind. I have absolutely no money to spend on this project.
I've installed elementary OS and hopefully it'll work.