I think that Anders Eriksson made a special driver in assembly in order to accelerate the text display, and the dirty hack part was that it worked on acustom resolution. At least that's what I remember right now...Hum, that was long ago, but if I remember correct I just made a patch to use 8x8 font and some higher resolution (you can never have too many lines of irc :). All that is long lost though.
I probably still have that somewhere. I used those 50-lines vcons, indeed for IRC. :o) I must have the sources somewhere too because I recompiled it to change the colors.
However, I think writing an optimized terminal emulator for GEM would be more sensible than virtual consoles.
Hmm, dunno, I still miss them on my Mac. :) On my TT they were especially cool since vcons didn't support the videocard, so I had the vcons on a tt monitor and GEM on a vga monitor. Looked quite impressive to non-atarians since two-monitor setups were not all that common yet. :o)