I was trying to find something that would print on the BBC Master and found a BeeBug dumpmaster rom.
./mame64 bbcm -printer ap2000 -romimage1 dmpmastr
It kinda works, but it seems to get its workspace corrupted when I do a *LDPIC. You're supposed to be able to hit CTRL+SHIFT+@ (mapped to backslash) to make it dump.
*LDPIC is a custom graphics loader on the Acorn User Gallery discs which runs in workspace at &900, so not too surprising there's a conflict.
The most popular printing ROMs at the time were Dumpout 3 (dumpout3) and Printmaster (prntmeps), but not sure if they have a hotkey dump feature.