First off, many thanks to Jude Nelson, Ralph Ronnquist and all others who have helped with vdev.
Below is some feedback from my initial try with vdev and request for help (see item 8) to get me a bit further.

Testing vdev on old Dell Inspiron 1525 running devuan beta2, kernel 3.16.0-4-amd64

1) I copied Ralph's packages from https://git.devuan.org/ralph.ronnquist/vdev/tree/master:
libudev1-compat_1.2.1_amd64.deb
libudev1-compat_1.2.1_i386.deb
vdev-initramfs_1.2.7_amd64.deb
vdev-initramfs_1.2.7_i386.deb
vdevd_2.0.2_amd64.deb
vdevd_2.0.2_i386.deb
to a local repository I maintain using aptly (this mostly contains mythtv packages I have compliled for devuan)

2) ensured my local repository was in /etc/apt/sources.lst

3) ran synaptic and "reloaded" (updated) then selected and installed libudev1-compat, vdev-initramfs and vdevd
NOTE: package libudev1-compat would not install properly with error message:
"trying to overwite '/usr/include/libudev.h', which is also in package libudev-dev_215-17+deb8u5"
I therefore uninstalled libudev-dev and retried libudev1-compat which then installed without error

4) As root ran: /usr/share/vdev/vdev-install.sh dialog
and choose vdev then rebooted.

5) All appeared to work as expected (including WiFi)

6) Tried setting PERSISTENT_INTERFACE_NAMEs in /etc/vdev/ifnames.conf
for three network adapters internal WiFi, internal ethernet & external USB ethernet adapter
This apparently had no effect even after reboot until I reran vdev-install.sh and rebooted (this is presumably
expected behaviour? but probably wants documenting)

7) Attaching a USB stick or a USB disk drive did not produce a "mounting" icon on the xfce4 desktop (as would happen with udev on this machine)
although everything was setup okay for manual mounting. Is this expected behavior? Running vdev-install.sh, choosing udev and reboot
and the xfce4 "mounting" icons again worked as expected, reverting to vdev and the xfce4 "mounting" icons failed to work.

8) I attached an external USB HDTV adapter (PCTV 290e) and the expected /dev/dvb devices were created.
However for to test this further on a proper multi-tuner mythtv backend (with the need for consistent and meaningful names),
I would need to be able to recreate the following udev rules in vdev:

# PCTV 290e single tuner USB stick
# --------------------------------
# Create symlinks /dev/dvb/adapterPCTV290e/* pointing to PCTV 290e adapter (has unique attributes, so can find wherever it is)
KERNEL=="*demux0", SUBSYSTEM=="dvb", ATTRS{product}=="PCTV 290e", ATTRS{serial}=="00000006LKWJ", SYMLINK+="dvb/adapterPCTV290e/demux0"
KERNEL=="*dvr0", SUBSYSTEM=="dvb", ATTRS{product}=="PCTV 290e", ATTRS{serial}=="00000006LKWJ", SYMLINK+="dvb/adapterPCTV290e/dvr0"
KERNEL=="*frontend0", SUBSYSTEM=="dvb", ATTRS{product}=="PCTV 290e", ATTRS{serial}=="00000006LKWJ", SYMLINK+="dvb/adapterPCTV290e/frontend0"
KERNEL=="*net0", SUBSYSTEM=="dvb", ATTRS{product}=="PCTV 290e", ATTRS{serial}=="00000006LKWJ", SYMLINK+="dvb/adapterPCTV290e/net0"

I have no idea how to do this! Any help with this would be appreciated.

9) Any other tests you would like doing?