Hello. I found nice programm OSC Commander (http://osc-commander.com/) and made layer for ardour / mixbus.
In OSC Commander Editor you can add some objects (float/integer) - so in this we can add faders (but i found bug with it, but developer says can fix it).
So, hope you enjoy this =)
Looks good. The latest git versions of Ardour include /ardour/routes/gainfader rid value which is probably nicer that abs or dB. It takes a fader position from 0 to 1 and sets the Ardour fader to the same position. This makes the fader more usable as it expands the adjustment range that is most useful. (0dB to -30dB or so)