In Amsterdam, if you wanted to print at A0 size, you just did. At conferences, there's not enough time to let everybody talk, so most people tend to present their research on a poster. And that requires more than a standard printer! The faculty I was in had its own A0 plotter, especially for conference posters. It was the same at the Polar Institute. In Plymouth, things worked differently; if you needed a poster, you just handed your text and your figures to the cartographers, and they made it into a poster that would be prettier than you could ever do yourself. And they had it printed for you too. Very luxurious!
Here in York it's different again; no cartographers to make your posters, but a commercial printing shop on campus. You bring in your design on memory stick, and the next day you can come in to pick up your nicely shiny poster. I'll be presenting my Icelandic stuff in Liverpool soon. The poster is ready!