The following patch adds the keycodes for F13-F24 on a standard PC-122 terminal keyboard.
Doesn't seem to conflict with anything else I've found. -- Creamy
--- wskbdmap_mfii.c.orig Tue May 24 13:23:46 2011 +++ wskbdmap_mfii.c Thu Mar 14 13:10:56 2013 @@ -130,6 +130,18 @@ KC(83), KS_KP_Delete, KS_KP_Decimal, KC(87), KS_Cmd_Screen10, KS_f11, KC(88), KS_Cmd_Screen11, KS_f12, + KC(91), KS_f13, + KC(92), KS_f14, + KC(93), KS_f15, + KC(99), KS_f16, + KC(100), KS_f17, + KC(101), KS_f18, + KC(102), KS_f19, + KC(103), KS_f20, + KC(104), KS_f21, + KC(105), KS_f22, + KC(106), KS_f23, + KC(107), KS_f24, KC(127), KS_Pause, /* Break */ KC(156), KS_KP_Enter, KC(157), KS_Cmd1, KS_Control_R,