I've been using a self-made swiss german (sg) kbmap for a couple of
months now.  So far the only issue I've encountered is that the sg
layout uses AltGr quite a bit and vncv(1) maps AltrGr to XK_Meta_L
(see /sys/src/cmd/vnc/kbdv.c:47).  But since that's not really an
issue with the kbmap itself I feel ok attaching it here and suggesting
it'd be added to the distribution.

For reference: https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/KB_Swiss.svg/1920px-KB_Swiss.svg.png