Diccon,
   I played with this a little over the weekend.  It seems that the
BIGGEST problem is that Linux, by default, sends ASCII DEL (0x7f) when
you press backspace.  I tried mapping that in the SED keybindings, but
LOAD.KEYS does NOT recognize '@?' as a control-key (^?).  This is
probably a bug in SED.   I finally gave up and decided to tell Linux
to use ^H for the backspace key.  Then, in terminfo.mods, I remapped
kbs to ^H as well so that QM in command mode and SED work the same.
(It IS a pain.)  On the bright side, when I was messing around with
SED and key bindings, I got PageUp and PageDown working with my PageUp
and PageDown keys. :-)
GaryW