... it hasn't helped that there are no lkm devices in the NetBSD tree

huh ?


splode ~> ls -l /usr/src/sys/lkm /usr/src/share/lkm
/usr/src/share/lkm:
total 13
-rw-rw-r--  1 mrg  wsrc   456 Aug  3  1996 Makefile
-rw-rw-r--  1 mrg  wsrc  8664 Aug  3  1996 README
drwxrwxr-x  5 mrg  wsrc   512 Aug  3  1996 misc
drwxrwxr-x  5 mrg  wsrc   512 Aug  3  1996 syscall
drwxrwxr-x  4 mrg  wsrc   512 Aug  3  1996 vfs

/usr/src/sys/lkm:
total 7
-rw-rw-r--  1 mrg  wsrc   110 Jan  7 21:48 Makefile
-rw-rw-r--  1 mrg  wsrc  2002 Jan 18 13:30 README
-rw-rw-r--  1 mrg  wsrc   811 Jan 18 13:30 TODO
drwxrwxr-x  7 mrg  wsrc   512 Feb 19 07:14 compat
drwxrwxr-x  4 mrg  wsrc   512 Jan  7 21:46 netinet
drwxrwxr-x  7 mrg  wsrc   512 Dec 20 18:10 vfs


the share/lkm has existed for as long as NetBSD has supported
LKM's, and the sys/lkm has existed since before 1.2 was released
(but _after_ 1.2 was branched).