>This only goes to demonstrate that command line editing and stuff like
>that should be in a console driver (either in the kernel or in a userland
>app such as screen). That way, *all* programs benefit.

Umm.. how about using something like fep? From the man page:

#FEP(1L)                                                   FEP(1L)
#
#
#NAME
#       fep -- general purpose front end processor
#
#SYNOPSIS
#       fep [-emacs|-vi] UNIX-command
#
#DESCRIPTION
#       Fep is a general purpose front end processor applicable to
#       most UNIX commands that features vi(1)-  or  emacs(1)-like
#       line  editing and a command history mechanism like that of
#       csh(1).

And the conditions for distribution seem OK (from README):

#Distribution
#
#        Distribution without fee is permitted as long as all
#        copyright notices are included.

The author is Kazumasa Utashiro (utashiro@sra.junet). I don't know
where the master copy lives. I found fep at ftp.funet.fi. Compiled
with minimal changes on NetBSD.