Edit: /etc/console-setup/remap.inc (1359B)
# The content of this file will be appended to the keyboard layout.
# The following is an example how to make Alt+j switch to to the next
# console and Alt+k switch to the previous console.
# Uncomment the following lines for Linux. Notice that everything is
# replicated for all possible values of the modifiers shiftl, shiftr
# and ctrll (shiftl and shiftr are used for groups 1..4 of XKB and
# ctrll is used to fix the broken CapsLock when Linux console is in
# Unicode mode).
# alt keycode 36 = Incr_Console
# shiftl alt keycode 36 = Incr_Console
# shiftr alt keycode 36 = Incr_Console
# shiftr shiftl alt keycode 36 = Incr_Console
# ctrll alt keycode 36 = Incr_Console
# ctrll shiftl alt keycode 36 = Incr_Console
# ctrll shiftr alt keycode 36 = Incr_Console
# ctrll shiftr shiftl alt keycode 36 = Incr_Console
#
# alt keycode 37 = Decr_Console
# shiftl alt keycode 37 = Decr_Console
# shiftr alt keycode 37 = Decr_Console
# shiftr shiftl alt keycode 37 = Decr_Console
# ctrll alt keycode 37 = Decr_Console
# ctrll shiftl alt keycode 37 = Decr_Console
# ctrll shiftr alt keycode 37 = Decr_Console
# ctrll shiftr shiftl alt keycode 37 = Decr_Console
# For the same result on FreeBSD uncomment the following lines:
# 036 'j' 'J' nl nl nscr nscr nl nl C
# 037 'k' 'K' vt vt pscr pscr nl nl C