I have discovered that the Ersatz-11 emulator will even work on Windows Mobile, if you use DOSBox. Here is an HTC tytn II mobile phone pretending to be a PDP-11 and running RT-11. Is this the smallest piece of hardware to ever run the RT-11 operating system?
But it is VERY slow. It took about 30 minutes to draw my ASCII mandelbrot. So it's not exactly practical. As you can see there are also some screen rendering issues, although I could probably fiddle with more settings. But I think that it's one of those things where you go "oh yeah" ... and then never try it again.