I've now uploaded a first beta, vdevd_2.0, that includes the mechanism
for dealing with (hand) compiled udev rules, and also includes the
scanner rules and modem mode switching rules. The mechanism is just a
straight-forward (extended) use of the "hwdb" database, which already
was set up to hold properties keyed by device identification
(essentially vendor+product). So I added a helper that processes these
properties, and e.g, sets group ownership to "scanner" when the device
has the property "GROUP=scanner".

This only affects the vdevd package, which now is version 2.0, and
otherwise you'd use the latest libudev1-compat_1.2.1 and
vdev-initramfs_1.2_5.

If you are keen you should touch "/root/ralph.log", and then vdevd will
drop log pearls from the helper script "/lib/vdev/compiled.sh" into it
when devices are added. This particular feature will of course be
removed at 2.1.

With that mechanism and it's pre-seeding, vdevd is essentially ready,
and so is libudev1-compat (although I haven't really plunged into that
bath yet, so I don't know for sure).

However, vdev-initramfs still needs attention. At the moment it combines
initramfs building of vdev in competition with udev, and the set up for
sysvinit, also in competition with udev. (The latter of course only
makes sense where sysvinit is used, and maybe it should be separated
out. But then one would need two hands to manage the udev competition,
and it'd double (or more) the possible strange failure cases, and my
work load)

Note that the start/stop script in /etc/init.d/vdev still belongs to the
vdevd package, which thus also shows preference for sysvinit. But, if
you don't want vdevd in the initramfs (who does, really?) and/or have a
different init scheme, you should skip installing the vdev-initramfs
package, and with some manual blessing you'll easily get the vdevd magic
happening where you need it.